It seems so, as far as my limited (really!) knowledge goes. It is what I got from people that hacked with N900's charging/USB hostmode bits, and practice seems to reinforce that.

Why a moot? BL-5J is so incredibly popular battery, that I don't see it perishing from alternate-manufacturers sources in next ~15 years, if not more. Also, due to lack of "intelligent" battery chip in cell itself, it will be always incredibly easy to modify <any_new_~3.7battery_that_isn't_bigger> to work with N900. Well, as you may be aware, I'm even working on putting 2x 18650 LiIons there I wouldn't be afraid of obsoleting due to lack of batteries.

Also, in case of always-from-AC scenario, it have some benefits, to keep a battery inside (one that you don't care about actual capacity after years of usage). It acts like a integrated UPS

I'm all for new accessories for N900, but I doubt that chinese folks would find it profitable - most people would just stick to have any random battery inside N900, even for always-AC case - for reasons mentioned above.

OTOH, chinese manufactures even produce a N900 motherboards (without any parts, just PCB's), which I can't imagine a market for, either - so, everything is possible

It's because using another X display doesn't "forward" images itself - that wouldn't be possible without some compression (bandwidth), after what you would, basically, get VNC. AIUI, X just sends required data, and device with monitor physically attached to it (RPi, in that case), does all graphic job.

Both RPi can route input back to N900, but, if one would like to mess with it, RPi can also route raw USB clients (not only input) back to N900, even in N900-as-client scenario - through USB networking, and one of FOSS USB-over-IP protocols (one similar to THIS). Keep in mind, that I haven't attempted it myself - it's just that there are no technical/logical reasons, why it shouldn't work. I'm just not sure if anyone compiled USB-over-IP clients for N900, so some compiling work would be required (and, as said, to actually have certain device working with N900, you need appropriate modules in N900 kernel- just like when that device is connected to N900 via physical hostmode).

Thanks a lot, but I'm just a small firefly here - look at our kernel hacking guys, half of hardware modifications wouldn't be possible without their work.

Well, some people (*wink wink* don_falcone *wink wink*) would just say "get a separate netbook/camera/whatever for that, it will cost the same or less", and they're probably right But. I just like to "stretch" N900 capabilities. After all, it's fully-featured computer (mobile one, but that doesn't mean it should do less), so if it can do some things in practice, why not? Having all those "beautiful things in small package" that we always carry with us (due to having phone functionality), is nice thing.

I used to have "external" digital compact camera - the problems is, that everytime I seen something worth photo'ing, I haven't had it with myself (murphy law), so I ended up doing shot with N900 anyway. After few such situations, I decided that messing with N900 camera is more feasible in practice, and got rid of compact one, focusing on adding camera tripod mount point for N900's mugen cover (which resulted in ugly mod, thatIi'm using up to this date). Thinking about all of fussle it required to put it into mugen cover, I thought "why not to make a whole replacement backcover using better material". And, why not to make whole body, then? That's how replacement body project was born, stretching to it's current layout.

It's pretty much the same with everything else

/Estel