Are manufacturers making a flip flop hub in a 130mm rear spacing size for road frames? Also, I understand that the norm with these hubs is fixed on one side and free on the other. Is it possible to run a single cog freewheel on the fixed side as well as the free side? Thanks.

A freewheel can also be run on the fixed side. It will thread on. I have no idea who (if anyone) makes a hub spaced at 130mm, but that's irrelevant. You can just get a long axle and spacers for a 120mm thread. It could be daunting for a newb, but the axle on IRO hubs is long enough and Tony will add spacers if you request it. irocycle.com