you can just crack open an inexpensive ($12) hyperglide 7-speed cassette, remove a couple of the cogs and replace them with inexpensive plastic spacers. keep the crank, remove any unwanted chainrings (singlespeed chainring bolts might be in order), mount any derailleur you want and use a single DT friction shifter. now it's a five speed. done.
or you can buy just use any hyperglide freehub and individual hyperglide cogs and build whatever you want. 1, 2, 3, 4, 5, 6, 7, 8, 9 or 10 speeds. chainline issues are minimal when a defailleur is employed.
Last edited by hueyhoolihan; 02-10-12 at 05:42 AM.