Thanks to Chris, Bill, and Greyhawk for the suggestions. Here's an update:

It proved to be impossible to remove (or reconfigure) shims to move the axle closer to the gear casting; Anything I tried caused the brake pads to interfere with the disc. Actually, to get the best fit between the brake pads and the disc, I had to add another .062 shim to the .180 already in place. So now I have a total of .242  (basically, 1/4") of shims between the brake mounting plate and the axle. The old Rosenhan brake mounting plate was .228 (not .210 as I previously posted). The new Matco brake mounting plate is .125, the difference being .103". So the axle, wheel, and tire now stick out .242 minus .103 or .138" farther than before - a little over 1/8".

Today I compared the old Rosenhan parts to the new Matcos to try and figure out what the heck was going on; The only difference I found was the thickness of the aluminum brake shoes and the thickness of the brake mounting plate. (I haven't measured the standoff bushings yet.) The old Rosenhan cast-aluminum shoes were ~1/32" thicker than the new Matcos. (Note: I was wrong when I said the new brake pads are thicker; They're still the same.) In summary, nothing jumped out at me to account for the difference in form and fit.

I've had to withdraw the previous Kudos I awarded to Matco. As we got further into this problem, their tech support started just sending me copies of drawings which were obviously not valid for installation in the Lancair. I sent them photos and actual measurements, but they simply ignored all of that and kept sending me the same wrong information. It's a shame they wouldn't work with me on this, but I'm clearly on my own now.

My middle gear door is already hogged out to allow the gear casting to nest right into it - I removed the core and used micro to make a nice, clean mold of the gear casting. After cleaning up the recessed area, I then layed 2 bid (?) bid over it. There's no room for further adjustment there and, besides, the puck housing and brake hose are in the way of further movement. Bending the aluminum bracket might gain me a little but, once again, the gear puck housing is the limiting factor; It's already smack up against the gear door.

At the moment, I'm leaning toward option 1 - removing some of the wing skin core and glassing over the removed area, but there is an Option 5: Reinstall the old Rosenhahn brakes. I already cleaned them up and replaced the puck O-rings, so they would be perfectly serviceable if I replaced the pads.