By switching the nine speed freehub body for the seven speed,
I gained axle length. so then I needed more metal plate back there
anyways due to high stresses at high speeds. so I just chopped
the derailleur hanger off of an old derailleur. used it on the non-drive
side. Also spaced out the rear chainstays a bit with one more thick
washer on the inside of drop out. Perfect. with this setup It's
really strong, looks discreet, and didn't cost much moola.
oh I just got what you meant by 'axle keepers' I used a cruiser/derailleur adapter
to mount the derailleur. and that has one of those funky backing plates that slides into
the drop out. the other side is a cheap derailleur hanger cut but still with
that funky bolt and backing plate that slides into the dropout.
Line these two up where you like them, tighten down, play around
with quick release to figure out optimal tension, and boom!
you've got a quick release rear wheel for your MB. Peace and
keep on riding!