Hi,
you're right, it might not work out or be a very close call. I'm hoping for the second. So the real question is how much of a difference there is between our steerer tubes. (I don't just have some 20'' frame, I have that exact frame in 20'') And I'm not sure what the 1'' difference in the seat tube translates to for the steerer tube. Playing around a little with a different stem, a different cable hanger and maybe even a different headset might win back the mms I loose by using it with a larger frame.
Have to ponder on that well, though. Well, the measurement would definitely help.
Cheers, Holger