Oh boy, that's an interesting question. There are 5 main flavors of FBM:
CGFBM (combat grade fusion battle mistress)- ordered directly from Busse Combat, and also at least one version from the Company Store (the "mudsnake")
FFBM (fat fusion battle mistress)- from the Company Store only
FBMLE (fusion battle mistress limited edition)- still available at the Company Store
Prototypes
Customs
Within each of these categories, there are several variations. I guarantee you there is nobody out there who has one of every possible combination- there are tons. When the CGFBM was offered, you could select from several blade finishes and handle options- lots of possible combos, similar to the way the ASH-1 is currently being offered by Busse Combat:
http://www.bussecombat.com/knives/index.shtml
And there is also the 2007 SE model, which is essentially a doublecut FFBM with G10 mags, IIRC.
All of the FBMs are very, very nice. There is no wrong choice. But there are a lot of differences between them. The CGFBM and the FFBM are quite different, with the CG being much lighter/ faster, and has the CBT (corrugated bevels). The FFBM is a very heavy knife, and is an extremely powerful chopper. The FBMLE sort of splits the difference between the two, and is probably the nicest out of all of the mistresses. (I don't have an LE yet, poor me.)
You can still find pretty much everything in the exchange if you are patient. There are several up there now.
Good luck! I'm sure someone will be along shortly to help you with some pics, if they haven't already, while I was typing this. (ETA- yup, there's Grimspoon!)