Dave Gray has been looking for folding pedals for several folding/travel bikes with different wheel sizes and frame layouts he has been building and experimenting with. A web search led him to Sheldon Brown's site and Harris Cyclery, which offers a quick-disconnect pedal based on a coupler much like pneumatic hose couplers. It is based on an MKS New RR2 pedal body with a special spindle that mates to the quick-disconnect stub. They seem to be pretty good quality in terms of weight, finish, bearings, etc. and they sell for about $70 retail on the web [Green Gear sells something that looks the same for about $110].