Honestly, I would either build one out of PVC coated hardware cloth(1/2") and buy the hardware from Martinscages.com(except use a tub like you house the snakes in for the pan), or you can buy one. I have pictures of one I built for my dwarves.

I HATE tanks for rats, UNLESS the rat is sick and needs confined, OR the rat is pregnant and close to birthing. Tanks do not provide adequate ventilation and it can scar their lungs very quickly from the ammonia buildup(unless you want to clean it every 2-3 days). Lung scarring leads to chronic respiratory problems from decreased lung capacity. Tank toppers are ok, I guess, but the rats can't really get off the wire unless they go down into the tank area(higher concentration of ammonia).

Petsmart has these nice wire cages, but they are just painted and not powder coated. I love Martin's cages, because they are BIG, easy to clean, and not expensive.

You can also build a cabinet cage out of melamine, and those look really nice. I have one for most of my girls and it is 3ft x 2ft x 4ft. Very easy to clean, but some of the shelving eventually needs replacing(I didn't seal it well enough in some places).

And I hope whoever said that rat people are nuts.. Didn't mean it.. Some can be, but those are the fanatics who never leave their house. I have pet rats and snakes, and I know that my friends don't think I'm nuts(even the rat lovers). Yes, my rats eat a mostly organic food mix, wellness senior dog food, they get fresh veggies most days of the week as well as some of what we have for dinner, and Mazuri lab blocks, but does that make me "nuts"? No, it just means I'm caring for my pets as best as I can. Just because a dog can be kept in a dark closet, fed, watered, cleaned up after and it survives, doesn't mean it's the best possible environment for that animal.

For me, feeders are feeders and pets are pets, there's a line that separates.