Did you get a look at the folding tandem they have listed on that same page? It looks really cool but the weight limit is kind of low at 325lbs.
Last Christmas, I bought a folding trike for a close lady friend of mine from Wal-Mart called the "Trifecta". It is a budget version of the "Port-O-Trike" also shown on that web page. It does fold fairly compact for an adult trike, and she keeps it in her living room next to the front door to use when ever she goes shopping to the local supermarket about a mile away.
I would say that Worksman products may have an almost "agricultural", unsophisticated look to them but they do last.