There is a bunch of info out there on getting the Treo 650 to boot
Linux.   The screen is a bit smaller than you like (320x320), but it
otherwise can satisfy your other wants/needs (you have to get an
802.11 SDIO card for wifi).   Not perfect, but might be worth looking
into.

-- 
Jay Kline
http://www.slushpupie.com/