Just thought I'd post up a photo of my latest project. I built this frame using a cut up old Raleigh cruiser and recycled most of its components. It's a reinforced mixte design, MIG'd up with a few sizes of .065 ERW tubing... probably similar to schedule 40 conduit. The frame weighs 25 pounds but can easily support 600+ lbs of people or cargo.
It's got removable pegs and running boards, and a nice deck that covers a beautiful radiused rack. Smooth shifting with the cruisers original 7 speed internal Shimano Nexus hub and coaster brake. It has a MTB front fork with cantaliever brakes, and handle bars from an old tandem.
I built this thing for burning man, hence the wild paint job. It was a huge success... spent the whole week taxi'ing people around.