I have gone ahead and ordered two RVHE's for the touch project.
Today I came across an ultra-cheap embedded PC, the KuroBox HG WR which lists for $149. It has a 266Mhz PowerPC, 128MB of RAM, 2 USB 2.0, and GigE with a quiet 22dB fan. It says there is an internal 6-pin serial connector as well. It looks like it doesn't have VGA of any kind. It comes with a base Linux install with telnet, ftp, and web.
KuroBox doesn't come with a drive, but can take an IDE drive. Perhaps a 1GB IDE Flash drive for dependability. There are also IDE to CF ($11.51) adaptors, so you could use a 1GB CF card ($41)