Thanks, guys for the suggestions (and the condolences). I must admit, I thought I had completely ruined the plastic, but I've lucked out somewhat. After I got home from work, I removed the canopy from the model (very easily as I had used Aleene's Clear Gel Tacky Glue and it came right off without marring the paint or surface).
Texgunner: I looked at getting a new canopy when I first started this model back in February (you can read through the build logs starting here: http://cs.finescale.com/fsm/modeling_subjects/f/29/t/142602.aspx?sort=ASC&pi240=79 ). Apparently, the only canopy I can find for the Razorback in 1/48 scale is from Falcon Models out of New Zealand, and Squadron is out of stock. Bummer.
Constructor & Rambo: I tried your suggestion of applying Future over one of the panes. It did clear up the frosting, but it left a residue after drying. It just doesn't get the Dullcote off by itself, and it still stains the plastic. Good thing to try, however.
Jgonzales: Brake fluid would probably work. I can't remember, but I think I soaked the bubbletop canopy in Purple Stuff and it removed the old paint without clouding the plastic. Not sure I would trust leaving it in there too long.
Italian Starfighter: Dipping it in alcohol was what I finally did, rather than swabbing it with Q-Tips. It not only got rid of the Dullcote, but took the paint off too! Since the canopy had been pre-dipped in Future, I suppose the 91% alcohol just dissolved it away, taking Dullcote and paint along with it. It only took about 15 minutes to work.
Gamera: I think we discussed earlier the dangers of lacquer coatings on paint. I was finally forced to use the Dullcote as my search for an acrylic flat coating in the local hardware stores came up empty! It seems to have worked okay on the model, though there might be a little frosting on the wings. It's hard to tell if it was the Dullcote or my use of paint thinner to streak the wings a bit. It doesn't look bad, whatever it was. The gun-streaks on the other hand are WAY overdone!
Flyitlikeyoustoleit: I was wondering where I could find a half-naked 1/48th scale female figure?
Wow, that Stuka really is frosted! Time just to place it in a snow-landscape, paint some white on it and call it "Russian Front - Winter 1943". As for removing the frosting, you might try the alcohol and Q-Tips on some sections and see how it works. Sure would be a shame for the model to be ruined.
Thanks, guys! Now all I have to do is mask and repaint the frames.
Gary