you might check out the Carvin Legacy 2X12 cab it has Celestion Greenbacks loaded in it for a good price.

Also, not many people ever consider 4X10 cabs but I've played through 4X10 (semi open back) cabs and the effect is really nice. The bottom end may not be what you're looking for but it is punchier and tighter than a cab loaded with 12s (generally speaking) and the highs seem a bit sweeter.

I've been thinking of mixing one of my rigs with one 4X10 cab and one 2X12

Just a thought.
http://shredlikehell.com