I guess I'd be fine with any layout, as long as it has four cursor keys and is remotely qwerty, qwertz or whatever.
The N900 has made me quite humble in that regard.

Just a thought:
Michael Mrozek, the developer of Pandora and Pyra, has invested an almost obsessive amount of effort into getting the keymat for the Pyra right.
The size is about the same as would be required for the Librem 5, but since the Pyra is a clamshell with nubs, I don't think you could just use its keymat. However, maybe getting in touch with Michael would still be useful.

Actually, I do care for NOT running Android (including derivatives) or any of the other mainstream mobile OSes, because I consider none of them to be trustworthy.
I'm hoping to put plain old Debian on a Librem 5 and just add some software that allows for basic phone functions.

That sounds promising!
Do you intend to include a keyboard backlight?

I think 4 rows would be totally fine. I mean, if you look at the N900's keyboard, a 4th row would essentially give you dedicated number keys, which in turn frees up a lot of potential for 2nd and 3rd level assignments.
The rest is more or less fine, at least considering the available size.

yes to backlight, will take time to develop keyboard, and with 3D printing it cost's very little, just takes time

And again depending on phone used or just make cases for various models, OS is up to user

This speaker looks promising:
https://uk.rs-online.com/web/p/minia...akers/1176049/
There can be 4x of these easily in the cover, 2x pr side


looking for inputs form the community if you have any tips on other hardware or better speakers

heehehee
I can see replacing blown ones allllll the time from turning the sucker up to "11"

personally I liked the n800 speakers...embedded front facing left and right taking up what front space there was...
Better sound delivery than the n810 or n900 out the ends...
(or much of anything else made since the n800 for that matter)

I have always been partial to utilizing as much space for speaker as possible on a device body

Ill try to get a few N800 speakers to test with, but the one i linked to according to datasheet is much better in both SPL and Watt's, normal phone speakers are under 1W and this is 1.5W with higher SPL at 1W, but will test quite a few just like the battery's, the best sound possible in the "smallest" space, the space dedicated to sound so far is many times bigger then N900

Sound wise yes front facing is better, but then screen has to be slided up and your hands not in the way, so im still considering side blasting, or maybe an internal fillet that directs sound to the front, this way it can be in a different shape then speaker, when i get more time ill start drawing up a prototype

do you remember the pop out direction movable periscope cam on the n800 , Frost?

THAT would be an ingenious design for a speaker system....
(and if pop out would take up too much room inside the device......)
then a rolling cylinder speaker with left right speakers on the top or bottom or sides of the device ...would be pretty innovative ...
could put recessed buttons on it for volume and other qualities...as well...to maximize the space...

that is a good idea!, have them pop out of the side or top, you want to view a video or play music only your not using the keyboard, and make a slide switch that operates the speakers movement and same time powers AMP and connects jack-detect so all audio goes through AMP, line out in headphones still possible at the same time if needed....

was also thinking about having them bulge out where the top of the screen is so your hands have a ridge to rest up on

very crude drawing, think rounder corners

An idea came to my mind and just want to ask. I have understood that it is possible to control the n900 with a computer through the usb cable. Thought that could it be possible to print an outer case for the n900 which would have a raspberrypi sort of computer set up in it. Then you could have a n900 as a phone but would put it on the case to use proper linux with better specs and better keyboard. If the the phone would be pushed in the case fom the side so that the keyboard on the phone is out, then the cases keyboard would be on top of n900 keyboard, the raspberry/whatever battery would be undeneath the display of the phone and the circuit board and stuff scattered around the case. If the phone would rang it would save the work in memory and you could just pull the N900 out and speak and then slide it back to case and continue. Of course this is not in anyway something that would fill peoples dreams but if there would be something like this and no dreams I think it could be one sort of solution.

good idea....

But why have to pull the n900 out of the case to answer the phone?

you really wouldn't need to...
Not if the "case" also acts as a "dock"...
then one could...in theory...
Just plug into the headphone jack talk set...(works good and are plentiful...)
Or ...
use the nokia bluetooth earpiece ....(I got one...works great..)
Or.....
take said n900 micro usb port ...and once slid in to the "case" connects to the microusb "dock" port...
and from the side of the case where the port is....one could have multiple split usb ports...(
I mean why have a "dock" (or "case" ) and not have port replication as well? Doesn't make a ton of sense...not to go that obvious next step ...

Hence...
one could use any telephony device that could function to answer calls with...up to and including a handheld telephone usb receiver...
(naturally the above use case is specific...and I think a more open Leste ...than maemo5 would be able to make use of peripheral devices more readily ....mind...)

If i make the base about 3mm thicker then the N900 base, i should be able to fit one of the cells i use for my e-bikes, these a LiPo battery's with only 1C (2C max) and that is for capacity, they do weigh 156g last i checked so it will be a bit heavy, phone has to be 5"+ to fit this but will enable the phone to have 10,000mAh, so usage time should be very good even under very heavy loads, when remembering back to the 3000mAh in the N900 this will be quite an upgrade.

On Speaker "design" im thinking about a release mechanism to let them "flip" out from the sides to be front facing when needed and side facing in normal usage so you can still use the keyboard, after they have been flipped out you have to click them back in, maybe this will change...., you still have to turn them on, this again puts power to 2x3W AMP and shorts jack_detect so all sound is going to amp, else when off the Android phones internal speaker is used - But this might also be subject to change, im always thinking about power efficiency and will have to do more tests on power usage of the amplifier to say if the power hit is very little, will make a hell of an alarm clock with this speaker system

EDIT: 1C rating means this battery will handle a 10A load (37W), so high power flashlight and much more is also a possibility, will do 20A for shorter time