[bliving]

Acard (acard.com) sells battery backed RAM/CFcard solutions for well under $500. There are compromises. It will fit your budget, but may not fit your needs.

[dejb]

Thanks for that. This page has a clearer description than the companies web site.

http://2xod.com/articles/ANS_9010_ramdisk_review/

Seems like it wouldn't be too hard to build this into motherboards so you could essentially have non-volatile ram for whatever purpose you wanted.