I got on the LSDiodes.com website and found the full-spectrum LED's were out of stock; it turns out they won't be available for around a month. I decided to get 3mm red/blue LED's and 3mm green LED's instead — the voltages are a little different, but overall they are much brighter (almost 3x) than the full-spectrum LED's.
I found a fence gate in the trash the other day and the tubing has the same inside diameter as a bicycle steering tube. I cut a couple pieces and tack-welded the top rear tube to the steering tube at a right angle. I'm using a grinder to create the rounded seams — sometimes I do a really good job and others will need some fill material. For the right angles, I've got magnetic holders to square them up. On the other end of the top tube, I welded a short length of 3/4" schedule-style threaded pipe. This way I can thread together the frame as needed.
The The University of Rochester Medical Center (601 Elmwood Ave.) is just down the street from my house, and they just recently closed their surplus sale site to demolish the building sometime in the future. During cleanup, they had thrown out the bed frames that rotate — I don't know what they're called, but they've got big steel hoops on each side. They had cut them up, but I snagged two pieces that I hope to use for the top of the vehicle frame. They were 72 inches across and 25 inches high &mdash approximately half of one of the hoops. I put representations in the CAD drawing and they're arcs from an 80-inch diameter circle. I'll need to bend them tighter than they are currently, but at least it's a start and will save me the trouble of starting from scratch with straight tubing.