Wouldn't you want the Giro 26 frame? You need the strength of the steel. These are rated for up to 275lbs.
The aluminum frames were max'd at 230lbs. in previous years, now at 250. That's still a pretty big difference for a relatively low increase in weight. You're going to add a ton of weight to this through customizing it anyway, so I think strength trumps weight in this case.
I'm building up a Cromoly to be my dirt beast. I'll shoot pictures once completed and do a brief write up.
~God Bless and Safe Cycling~
Riding to keep the temple in working order, Riding to keep the earth green, Riding to be a healthy father, Riding with my wife.