Here is a comparison of several piston options.
The exhaust side of the pistons are at the top of each pic except the last which it is to the right.

From left to right: Stock 74mm | Suzuki 75mm | Wiseco 78mm | Wiseco 79mm

Nice comparative anatomy shot.  

Not worked with the technology much but it looks like the dome height being larger would translate into more compression for the same fuel/air mixture quantity, a desired quality for someone who enjoys racing or more power.

Would this be like when I shaved the heads on my '69 Mach 1 except on the high side of the equation?

Dgyver, you may not know this off the top of your head, but feel free to guess if you can.

With any of these overbore pistons, what would the compression be assuming they were put into an otherwise stock engine?

Would there be piston-valve interface problems?

Stock compression is 9:1  
So just a guess with the the high domed pistons it would be around 11:1
(for reference my stock TLR is 11.7:1)

With the 78mm or 79mm pistons, you would need to run a higher octane gas.

No problem with piston-valve clearances. When I had a milled cylinder, milled head and high lift cams with the 79mm pistons, there was still plenty of clearance. The only problem then was the piston was hitting the spark plug. A little grinding on the piston took care of that problem. Not running the milled cylinder now since I was getting piston slap.

Whenever installing high compression pistons, it is best to check the clearances.