Bicycle Mechanics - new brakes--old frame

I have a set of new long reach brakes that I am trying to put on an old road frame so I can fit 700c wheels. The problem, and forgive my poor terminology, is that the center rod that the brakes attach to the frame with is not long enough for a nut because it is designed to thread into sleeve that comes through from the other side of the fork/brake bridge. I can't use the sleeve, though, because the holes in the frame are not big enough.

Has anyone run into this before. There are several threads suggesting new long reach brakes for old bikes when switching to 700c wheels, but none seem to address this problem. I would rather not spend the cash on the drop bolt devices from Harris Cyclery, but I do think that would fix my problem. What do you think about dremeling the holes a bit to accept the threaded sleeve? The other idea I had was to get some posts for cantilevers brazed on, but I have no idea what that would cost, and I do not want to have to have the frame painted. (Anyone know a frame builder in the Twin Cities?) I am planning on running 700x32 tires and some fenders would be nice for the winter so the extra clearance that cantis would afford would be welcome. Thanks for any suggestions.

Why don't you simply enlarge the hole?

I think you can get a through-bolt for your brakes. just ask the LBS

I've had to drill the holes larger to mount the newer type of long reach calipers on older frame several times. I see/have no problem with it, except if you have some sort of exotic collector bike which you don't wish to modify, in which case you'd probably not want to switch wheels anyway. Also, in case of steeel frame you may want to protect the exposed metal with a thin layer of clear paint.

The drop bolts, though expensive, will give you slightly more braking power.