Here are a couple other sites that sound interesting, but for me to figure out how to do it is over my head:
http://bcache.evilpiepirate.org/
https://github.com/facebook/flashcache
I'm really sitting on a nice computer and hardware and just trying to use more of its potential. I figure I can learn more about this linux stuff once I get it installed and start using it as my primary OS.
Okay, another cheap solution is to buy another fake RAID controller on PCI That is compatible with linux.
I've done that with a MINI-ITX board that ran a FREE BSD file server with dual disks, It worked right away after struggling for a day with my first motherboard that had an incompatiple RAID controller IC.
If you are talking about RAID on SSD!! forget it, it will wear out in a month!!
Depending on how much space you want for cache, we are not talking swap partition here I guess, Stuff plenty of ram in it and run a ramdisk for cache, It's faster than SSD no need for RAID 0 and dont die suddently.
I don't think you want to do this, but just in case:
If you want RAID for redundency, then it should be on physical drives, and not on virtual drives especially on a single SSD drive.
I've done some flash booting install of different distros, from embedded arch linux and up. To make a reliable and fast, system, move everything to ram, also temp file writing from the different processes running. The data you need after a reboot is written to a persistent partition on shutdown. It can be on your Hdd.