I had a 25-inch Super Mirage as well--bought it new in 1979, rode the dickens out of it, and recently gave it to my 26-year-old son, who rides it around Brooklyn. I assume it will get stolen eventually. Great bike, but I want to go with an English frame here.
I built up the rear wheel on a 36-hole AW I bought on ebay. I did replace the axle with a longer one, and ran it briefly on a 120 spaced Dawes frame with a three-cog rear block. It worked well, but with a double in front the shift pattern was idiotically complicated. Forget double shifts--it involved several triple shifts. Also, the bike was such a nice antique I ultimately decided it would be better to keep it all original. My idea here is to make something I can ride in winter and bad weather and not worry as it gets beat up and develops little rust spots, etc.
Here's a picture of that earlier Dawes build.