I've been working a bit on getting Bluetooth and GPRS/GSM support into my 2.6.x based kernel for the A780. Both are quite a bit challenging, even more than I initially thought so.
As for Bluetooth: In theory there is a bcm2035 chip, compatible to the Bluetooth HCI specification, attached to ttyS1 (BTUART) of the PXA270. However, there are some power management related additional signals hooked up to GPIO signals. I think I'm configuring them right, though. Also, there is some indication that the bcm2035 actually requires a bit of firmware loaded into it. Without a vendor data sheet and with only some stripped proprietary Motorola dload program this will require quite a bit more of investigation.
My initial 'demand' for Bluetooth would have been the possibility to use my Apple BT keyboard with the framebuffer console, providing a local console in case telnet dies for some reason.
On the GSM/GPRS front (yes, we actually want to use the phone as a phone sometimes), I've been wading through disassembled gprsv.o and mux_cli.o code. Both re-implementations are progressing slowly, but steadily.
The easier part seems to be mux_cli.o. I've now started to write some libusb based userspace code to test a ts07.10 implementation in userspace via the USB endpoints to the BP. Once the userspace code seems to be working, I can work on a kernel level implementation. The good thing about this is that there are actually quite a few GSM phones that support this multiplex on their serial port. So the resulting mux/demux driver will actually be useful for more people, not just Motorola Linux smartphone owners.