I could add that this list isn't restricted to US residents, so the old 'Buy American' line doesn't mean a thing to them. If you want CHEAP, then you have a choice: Pay some Chinese laborer $0.50 per day to make you a trike with quality materials and good parts, or pay a US laborer more but using cheaper materials. Chromo steel is hard, strong, and somewhat rust-resistant. Mild steel is not, which is why it must be used with such huge wall thicknesses; but at least it's cheap!

If you want US-made trikes that are't as low as a Catrike or Wizwheels, then check out Turner Recumbents and also Angletech Cycles.

Edit: I couldn't see that Turner makes trikes, but angletech has a quadracycle which, if memory serves me, can be ordered as a standard trike. Rotator also has a trike. Check the buyer's guide at http://www.bentrideronline.com for a more inclusive listing of trikes that are available. Note that 50 isn't old. I'm 50 and ride a lowracer, and another guy in my club is 65+, has two titanium knees, and rides a GRR.

On the subject of strength, typical yield strength for hi-ten a.k.a. 1010 steel is about 36,000 psi. OTOH, Chromoly has a typical yield strength of 110,000 psi (it can be made as strong as 225,000 psi; ) so a hi-ten frame needs at least 3 times the material to match the strength of what tightwad refers to as weight weenie stuff.