i did look at getting a beagleboard or similar with the aim of putting together hardware with the best open source support. the goal would have been to rebuild maemo either from source or rebased on a newer debian version/meego. the hardware choices would have been to allow remaining closed source driver issues to be resolved, hopefully removing reliance on closed source apps in the progress by reimplementation or using open source alternatives.

unfortunately i never got past looking for parts. dev boards had slower processors than desired, no a big deal breaker. found several cellular modems, apparently with drivers. wlan + bluetooth + gps + accelerometer + compass on a chip. storage i think was covered as well. Only needed screen and input.

the real issue is documentation. i'm not gonna go out and splash out cash on components without a decent guide in getting all of it up and running afterwards. pc building is simple, chuck in parts, install os and drivers and off you go. instead you need to get core os installed and booting, you need to set up telephony stack. you need to get the audio inputs and outputs correctly set up to work with it. you need to build applications/libraries to use it. then there's power optimizations.

some dev boards integrate more than others, i think a SE one had a modem, but are the compoents the best choice for support. the final hurdle, as smoku will tell you, is sorting out your own system-on-a-chip. having a working dev board is great but your not going to take that out and about with you.

this is not my area of expertise, so what little documentation there is is above me. I work in a pool. maybe someone with a little more experience would have more sucess.