Interesting that I just got back from the glass company discussing the same thing. You can do it yourself with a jigsaw, router and a jig (which you have to make) but it is a lot of work. Find a glass company in your area that uses a computerized machine for cutting glass (like a water-jet) and they should be able to do it for you.

 

I have a smoked one that I rarely use. It was about 2 or so inches to high. Traced it out with a cardboard template and marked it with a sharpie. Then did just as you stated. Smoothed out the whole thing with an orbital sander. Worked like a charm. It was very easy so I say go for it.

 

It's a piece-of-cake just as you described. I did mine on day one. Once you cut it with the jigsaw, use progressively finer sandpaper to give it a nice finished edge.

 

For some reason when I cut mine it left a residue or pulled the hard coating off left blotches on it I couldn't remove. Use the 3M blue tape.

 

OP As you stated, fine tooth blade and blue painters tape. Sander on the edges, and you can carefully use acetate to cloud the edges.

 

 

I cut 3" off the bottom of mine and re-drilled the holes. Doesn't matter if it's only 99% perfect because it's hidden.

 

if you use too fine jigsaw blade it will melt it instead of cutting it

 

use a "sharp" fine metal cutting blade and go slow