1) Wow doesn't use SLI "well", so you're unlikely to notice much benefit. Still, if money is no limit, sure, SLI 2 GTX295s for other games that do.
2) If you really want RAID0, then get a *good* hardware raid controller. The software raid controllers that come on commodity motherboards do not, in my experience, provide enough of a performance increase (if any) to be worth the hassle and risk. A good RAID controller with RAID0 can be significant. I've never personally tried it on SSD, but I've heard some good things.
3) 12G is plenty for WoW, but again, if there is not limit on money, why not?

Biggest things imo:

  • highest performance processor you can get. Right now this is OCd I7. Get the 975 (EE) edition. I would normally never recommend this because it's a giant rip-off, but you said money is no object and the unlocked multiplier can help with extreme OCing.
  • Enough RAM so you're not swapping. I have 12G and never come close.
  • Good video card, which is more than covered by your suggestions.
  • Following all the information on this site wrt how to setup your directories, hard-links, slave clients, etc. I can't stress this enough, it made the single biggest difference in the usability of my system. I'm not going to list everything off, it's all in the stickies if you read them.

Good luck.