3.0 is not open source and theres licensing issues. All custom roms so far are gingerbread based. As for auto rotation, we only have the cvs sytabex7 to test on which actually lacks an accelerometer, tilt sensor, and gsensor altogether so unless there's a way to fashion a usb sensor we will probably have to stick with either an on screen button or one of the two hardware buttons. There are various possible methods for sync as well. For instance on my android phone I have always preferred installing the samba app and having wireless access to my sdcard, if theres something specific you cant do with an app let me know.
Now as for the three or four other devices, without us having one it becomes alot more difficult to port, you could try our rom when its out and see if anything work for you, but if not we might need to setup a donation system to buy the devices to port too.