Here is the Harbor Freight hose reel (item #46342). It was $20, and took about 10 min. to put together. It doesn't include the allen wrench necessaryto complete assembly, but otherwise it went together nicely.
Starting the cable- I used a little pin to hold the end of the cable while winding
another shot of the clip
25' of 30 amp cable. It didn't seem to stress anything.
I'll try to remember to grab the 50 amp cable next time I go to the camper, and I'll take pics and do a little stress testing. If it works, I'll mount it andtake more pics!