i think that's a cool idea if your wife will let u do it. Lol!
some feedback:
1st - lot's of garages are not heated or don't have heating/cooling vents. what is your plan for ambient temps? will the water heater add heat?
I'll have to use a heater to keep ambient temps up in the winter and possibly a cooler in the summer. Not ideal but it is what it is. I am hoping the water heater will add some to the ambient temp, but I'm sure it will be minimal at most.
2nd - i would get the measurements of the rack u are buying and place 2-3 of them including the work table in your floor plan. does it fit? does the 8-10' x 5.5' size fit your future growth plans?
I am picking up a Vision 1756 rack which holds 32qt tubs. And then possibly a Vision V70 rack which holds 41qt racks. That's a good idea to get the measurements of those to see how much space I'll really have. If I go forward with the build, I will go with 10'x5.5'. I'll have to make my future breeding plans for in that space. It will be at least 2 years until any breeding takes place.
3rd - is this the room u plan on all your snakes/reptiles ending up in? keep in mind, it is good to have a QT procedure and set-up for new snakes. would QT take place elsewhere in the house?
For the time, it will be where most end up. My son will probably keep his in his T8 in his bedroom I imagine. I'll set up a quarantine area inside the house somewhere. I am not planning on a massive amount of snakes to start out so I'll at most have 1-2 snakes at quarantine at any given time.
just some thoughts. this is a great idea. good luck, post pix!