OK 3x30" ZOMFG!
In answer to the basic questions:
1. SoftH: I don't really know about it is a software hack which should enable you to run a game at that resolution (3x30") but you would need some SERIOUS GPU horsepwer for any new games...WoW is probably OK. But I digress I will let a SoftH expert answer that.
2. 'Triplehead' is the short name for Matrox's TripleHead2Go hardware solution. It is a box which you plug 3 monitors on one side into and you GPU on the other. It means your PC sees all three monitors as 1 big monitor. This allows you (for example) to enable SLI for greater graphics power.
product site
However there are several caveats on this:
the biggest (for you) is that the max resolution that the TH2Go can use is 5040x1050. ie 3x22" res. I run 3x24" (and they have the same ratio as 1680x1050...so there is no stretching) but it means that everything on the desktop is a bit fuzzy. It doesn't bother me at all (I though it would but after a week I don't even notice it). And in games I never noticed it at all. However maybe very different running a 30" screen at 1680x1050 res! Try 1680x1050 on one of your monitors and see :)
the other caveat is that many games do not support such high resolutions. Some you just cannot set them (Some games won't even do 2560x1600 so that shouldn't be much of a suprise) other games set the resolution but the FOV is all wrong ...
The green is what you would see in bioshock (before a fan hack was incorporated into the game!) using TH2Go, the red stuff is the extra bits you see sing a standard 5:4 or 4:3 monitor. So without proper (HOR+) support you get the resolution but actually see less! However there are lots of hacks and work arounds for those games that don't work...especially the popular ones.
With respect to WoW look at the detailed report
here
It says WoW is HOR+ (with Wrath of the Lich King) so you will be gaining a lot of visual realestate!
So there you go, good luck