Saw this on Jane Perrone's Grauniad piece about composting! Not sure the allotment old guys will take to it...
http://www.rolypig.com/
I love that! My kids would think it was brill !
The principle is fine enough - the old tumbler with knobs on - for the odd bucket of kitchen waste, but not much use if you have two or three barrowloads at a time of broad bean stalks, potato haulm, or just plain weeds to dispose of.