Yep, I had the pleasure to play with n800, my friend still got one and still using it (After I did flash it for him to the newest OS he is using it a lot, it's overcloacked now so I know what it's like. Expirienced that when I first overclock my n900). As far as he says the pidgin and facebook plugin works on this device, so this is my next step, get the n800 at make it roll

But now Im with 770, and I know exactly what you mean saying about advantages of n8x0, but there are some facts to consider, 770 is 2 years older and that means a lot.

"as far we can go with 770 we can continue it with n8x0 and go further"
Wow, what a thought xD

Now Im kinda running out of free time, so I will check your links in the evening and continue this conversation

Weeellll...
as to what you added in your addendum ...
as per point 1-
for the 770? probably not quite 2015
but I have no doubt that writing innovative alternatives to the 2005-2008 ones would bring it up to speed...well... perhaps speed and the 770 should not be used in quite the same sentence. (small rib at old bessy) ...I do believe it can be done...or rather.. done differently...to kinda sorta bring the 770 up to the present. Lotta work there though.
as far as getting users to come together to help make it happen for the 770. Not to sound defeatist. There just aren't enough 770 users now who are active...let alone members here...let alone have the skills, time, or inclination to develop for the 770. I fear it will be solitary work. For myself I pull out old bessy about once a year and muddle away on her...and then put her back ... My focus has been the n8x0 device line hackery-wise and there are few enough people developing on them...(though there is a steady growth of new members)..and my n900's for proper daily use...
point 2- I think a patch would take alot of time and manpower ...skilled ...which isn't there for the 770 any longer..(perhaps I'm wrong...but 2008-2009 saw too many skilled members migrate to the n8x0 and n900...otherwise the 2008 hacker edition would be more polished, finished and something newer replacing it...)
point 3- yup ....but you can try and see how far you get.
point 4- the n8x0 has more option and potential for work ..(.not to knock my 770...I love it for what it is, and does..she is beautifully retro in todays world)..(just for an example ..just look at all the os's and wm's which fully work or partially work for the n8x0...I think it eclipses what the n900 is able to do..I'm sure the neo900 will blow everything out of the water...but still..the n8x0 is quite impressive..).has a larger active community and new people coming all the time and still has some people developing....
As with any device line ....getting people involved is the question...
Best suggestion is...the more you work at making things work and function...new programs, patches, fixes, updates whatever...the more people gather...critical mass by the single match ...so to speak.
Nothing else works better...and it will save you disappointment ...just plug away do what you can and make things better....the results of your success and the ability to measure your success will be that people will gather as an "effect" of what you do...their number being in parallel with the greatness of your accomplishment. Meaning...more new people getting a device...more new members joining...more old members coming back...more people wanting to make and create ....and in the end you get what you needed in the beginning...

addendum:
as per your last post...
That was admirably good of you to get your friend's n800 up to speed...
If it were me and I not having a n800 (and a complete lack of a moral center )...I would have said to your friend..."that old piece of junk...nah...not worth puttering with...who needs more useless devices cluttering and filling space around the house?...you just keep playing with that fabulous ifone of yours and why not just give that old-piece-of-scrap-electronics n800 to me...I'll take it to the recycling depot for you..." muahaahahaahaa...
Darn ethics and morals...sigh...well... you did the right thing...
tell him about the posts at the bottom in my sig. Best thing is to clone to card. If he doesn't already know that is.
yeah..the n800 is grand with the 2 card slots...excellent for messing with sooo much...shame it doesn't have a built in keyboard. N810 is fabulous ..the bestest keyboard on a mobile device I have ever ever ever used...shame it doesn't have 2 card slots...hehe...yeah man...keep your eyeballs peeled for a n800 and n810.