I have DSP working too. What I also have is modified fbdev-sgx which I've been trying to adapt to work with recent Xorg, kernel and latest sgx drivers from TI. So far it partially works but is slow and crash prone. Both 2d and 3d acceleration works fine on framebuffer without X though. What X driver are you using with Ubuntu?

Extra buttons already work, using them is just a matter of userspace configuring and/or scripting. Cameras and sensors are of no interest to me at this point as there are alot of more important features to get going, but surely I'm going to look at them at some point.

Currently I'm trying to get charging to work. I have a kernel with Pali's charger driver which I think is already working, but I've had no luck with that yet. Other solution is to do this from userspace, which is currently the option I'm going with. This is already working thanks to Joerg and I'm about to adapt his charging script to get automatic charging from wallcharger. That should be enough for now.

Kernel package will come when I've packaged the essential n900 specific stuff so getting (command line) installation of Arch to just work by installing a package group.

As a comparison after watching your video, I got boot time of 7 seconds to console and from there few more seconds to Enlightenment. Class 4 mmc and ext4 fs.