I have heard of 2 barrel aluminum intakes, but must be rare. My personal hope is to rig MPFI in a cheap 1 barrel alum e-beam weld intake. I have the parts, but way down on my priority list.
I know MP used to sell a 2bbl alu intake. If you are going mpi on a 1 bbl intake you can get a sand cast aluminum 1bbl. I can't remember where mine came from, but I think it was a 87 ram. I have heard the welded intakes are prone to crack. It would be a shame to spend time having bungs installed just to have the intake crack.