Really there are two choices:

1. Get a hub spaced at 130mm. I think a number of people have suggested options here: Van Dessel, Phil Wood, Goldtech and White Industries etc.

2. Respace an existing 120mm hub by swapping the axle and adding spacers.
Harris Cyclery state that you can do this to: IRO hubs (claim theres enough threading on the axle so would just need spacers/washers), Surlys, Suzue ProMax and Suzue Basics (just need spacers here too), but you can do this to most hubs if you can find a suitable replacement axle.

See http://www.sheldonbrown.com/harris/fixed-hubs.html

So now you have a ton of options, though the Suzue Basic should be used only if you hate your bike.