Where can you get a good derailleur for a 3 speed freewheel?

[Floont]

Where can you get a good 3 speed rear derailleur for a 3 speed freewheel?

Thanks!

 

[vanilla ice]

I'd try a non-indexing from an old roadbike with 5. Adjust the stops waaay in and you should be good. I have an old early 80's RD stops adjusted for a modern 8 cog and it works fine. Or an old mtb one should be the same thing.