The SunXCD large flange cassette hub is one of the only hubs available in either 120mm or 130mm spacing. The 120mm spaced hub has a shorter free hub body, and will only accept modified cassettes (up to 6 speed). Similar to the Grand Bois rear hub. The 130mm hub is standard 8-10 speed. Both use Shimano cassettes. High quality Japanese sealed cartridge bearings with very well machined cones to keep out road grime.
There is currently only one available cassette on the market for the 120mm cassette, made by Grand Bois. Alternatively, you could make one up using single ring cogs and spacers.