To read a thorough step-by-step description of this build alongside photographic build documentation see this link to my RecycleCycle Flickr gallery.
Front-end: 26" Raleigh mtb
Rear triangle: 20" Trek mtb
Top-tube Two pieces of 1" square steel tube (from a salvaged grocery store shelf)
Horizontal middle section bars: tubes cut from other bike frames
Rear rack: 1" square steel tube (from a salvaged grocery store shelf) and OSB wood wrapped in reclaimed vinyl banner on top.
Rear tire and wheel: 36 hole, 20" bmx tire with 5 speed cassette and derailleur
Rear brake: cantilever
Chainrings: three rings (no derailleur - shifting is done manually, by hand)
Handlebars (driver): super long, swept back cruiser-style bars
Handlebars (passenger): stem clamped to driver seatpost with cut-down handlebar provides handle for passenger
Front tire: 26" mtb tire