Good point on Saudi Arabia, it would be interesting if they had kept a more open (non-aligned) purchasing line (spell O-S-O-R-I-O for me...
).
I'm not sure Imperial Iran would have got so much 100% US hardware, they also had a number of European/unaligned suppliers. Remember they were about to get about 1000 Challenger tanks, which would remain in line for some time. A Magach-like upgrade for their old Pattons would be interesting.
Bradleys are a thought, I think they were on to LAV-25s in any case, and some systems are common. In the 90s CFE-treaty context, it would be interesting to figure if they could get large enough quantities of surplus Leopard-2s in good conditions, for the first good Desert Leopard...
Modern F-16s no doubt, a replacement for the F-14 is a good question. Integrated defense with top-notch Patriots and assorted radars I'd say at first.