The Downtubes would have been perfect but they are aluminum.
I have done tons of research and have the tools to do up my Twenty (already had the BB converted) but I still think it's a bit more work than I have time for.
Looks like so far the Dahon Speed D7 is the frontrunner if I can find one around $300.
I see some China frames out there for cheap as well from hi-ten steel, in my mind there is no difference between them and a Raleigh Twenty, the Twenty is just heavy hi-ten as well and on mine the welds are hideous, would have to fill them all in if I want it to look pretty.
BTW The Thor page wasn't loading when I posted that, but now I see the adapters.