Building is fairly cheap. I built one tank already, less than $100 total, and now I'm building 10 tanks soon.
Solid cages work fine. So long as there is adequate ventilation, and the temps can be maintained, it's fine. Contact AP, and tell them what you need, and ask if it's possible and for a price quote. It would probably be about $250 before shipping.
I would ask if they can install a regular bulb fixture for the top of the tank. Ask for something rated up to 100w if possible, just so you have room to play. You may need to get a higher tank to make space for the bulb safely. You could us a Mercury Vapor Bulb in this, as it provides heat, light and UVA/UVB I believe.
Another place that's pretty much like AP is Boaphile Plastics.
http://www.boaphileplastics.com/ This is where I was thinking of getting my tanks from before I decided to build.
If you decide to build, there are several older threads of how to and suggestions on the site. There is also an enclosure part of the photo album. When I begin building my tanks in the next week or 2, I'll post a step-by-step thread, as well as suggestions and things I've done wrong. Talk to Zach, as he built his own tanks, and ask him for plans, suggestions and things he would not do if he did it again.
Good luck. You have a few months before baby season where you can get everything bought or built, and ready for the new skinker.