In my opinion the problem with today's diamond frame bikes revolves around the placement of the components not the quality of the parts. As much as possible I try to use existing 2nd hand bike parts, not just because it's easier but also to save money. I also find that as other see the work being done they target you with their surplus machines. Design pitfalls It seems to me to be a given that when people build a recumbent cycle they stray from the existing designs adding at least a few of their new ideas. If you're one of these people here's few tips to keep in mind.
Trikes Be careful with the seat to crossmember distance on tadpole style trikes.
The rider's calf muscles and heels sweep an arch that can easily interfere with the crossmember. On many machines it's almost too late to change this after it is welded up and can make for an unrideable cycle. There's a lot of force on the crosmember on a trike. If you choose to have a main boom pass on the same line as the crossmember I'd suggest you cut the boom for the fit not the crossmember. Bikes Seat to steering neck to bottom-bracket distance on SWB bikes can be tricky to get right.