option 3 for front mounting: Use the short recessed nut, but don't put it through the back of the fork. Instead, push it up into the inside of the steerer from the bottom. You can reach a 5 mm Allen wrench in through the hole in the back of the fork, and poke the short caliper bolt in from the front. You may need to shorten the recessed nut slightly to get it to fit inside your steerer.
In that case, I'd go for a recessed type nut with a filed washer.
There is also a nice idea from Sheldon right here: http://sheldonbrown.com/calipers.html#mounting
option 3 for front mounting: Use the short recessed nut, but don't put it through the back of the fork. Instead, push it up into the inside of the steerer from the bottom. You can reach a 5 mm Allen wrench in through the hole in the back of the fork, and poke the short caliper bolt in from the front. You may need to shorten the recessed nut slightly to get it to fit inside your steerer.
Seems a cool idea!! Not sure it'd fit your steed.