I haven't read the thread, but had a thought I wanted to put out there and this seems to be the right place.

Wish item for the N900 or future devices: Video out.
I just got a HD tv and went through the devices in my house for compatability. I've dismissed the video out on digial cameras (and still doubt i'll bother to connect a camera EVER). But then I looked at the N800 and wished I could connect not only internet but MP4 playback device. Perhaps this would have very narrow appeal.*

Then the today I find this device 'Neuros digital recorder' (versions have been around a while and discussed here before). It redoubled my wish to be able to connect my N800 (and now for video in). Now that I type this, I seem to recall archos had a docking station for recording. Either way for now, I'll probably just use a full pc, but that still won't have video in.

*Which reminds me of a request I probably posted here before:
Expansion Capability. Give us some kind of expansion slot. Maybe a full SD card slot open to the top (like palm treo). We can use it to add whatever we need. All I can think of as existing now is wifi SD cards, and GPS. But it could be my above mentioned Video out, an IR LED (to use as a remote), radio tuner, maybe a camera. Other industry specific thing like walkie-talkie chip, multimeter, device net node, PLC, maybe a barcode scanner (laser emitter for use with the camera).