'Dime Scale' refers to the old comet and other kits of the 30' and 40' which cost a dime. Most were about 16" WS. They are simple, sort of scale models. There is a 'dime scale' FAC event that allows these old designs and other design that are judged to be similar in construction. Building techniques and materials must be what was common back then. Some of the rules are: no laminated wing tips or tails, no preformed or plunge molded canopies or cowlings, no CF or boron fibers, etc. Some examples are on Dave Lindsey's site: http://mywebpage.netscape.com/dmlivesay/index.html
'Peanut scale' models are built to a size limitation of 13" WS, and in some odd configurations, to a scale where the fuselage is 9" long.
'Walnut Scale' is like peanut, but the limit is 18" WS, and 'Pistacios' are smaller than peanuts at 8" WS.