Funny, Me and Adam were talking about these at the pub meet last night.
512MB is plenty for an embedded application and I note there are SDIO and GPIO ports so adding more flash via a SD card should be fairly trivial.
I have used foxboards for several embedded linux projects and they only have 8MB of Flash and 32MB of Ram, although I have just generally popped an SD card on a few of the gpio pins and used a kernel module that does SD cards over GPIO if I have needed more...it's slow (even more so on a 100mhz processor) but it's handy for logging etc.