If you need lots of RAM, check out Leaf Lab's board called "Native"
which has 1 MB:
http://leaflabs.com/devices/#Maple-Native
!!Dean
or for the same price scare yourself with one of these (Tiny6410 Stamp):
ARM11 533MHz 256MB Flash, 256MB RAM USB host, SD interface, 4 ports but
not a lot more
http://www.friendlyarm.net/products/comparison
72 USD for one from here:
http://www.aliexpress.com/store/201108/210007544-483816958/Freeshipping-F213B-FriendlyARM-Tiny6410-Stamp-Module-533MHz-S3C6410-ARM11-Processor-256M-RAM-256M-NANDFlash-Development-Board.html
(same chip as used in Samsung Galaxy Spica)
meanwhile we wait for raspberry Pi...
http://www.raspberrypi.org/