There are now many vendors out there that do PVC enclosures. Probably the most common name is Animal Plastics. You can get it built to include lighting, sliding or swing doors, heat panel (floor if, if preferred, but not necessary), door locks, and basically very high quality construction. I have used only one other PVC brand, and the quality is 100x LESS than the Animal Plastics. The only issue with Animal Plastics is the lead times. Often you will order, and you're going to have to wait a few.months, since they are made to order and get a lot of orders. Worth the wait of you can do it, but just keep that in mind.
PVC is much easier to maintain heat and humidity. And definitely easier to source the heat (in my opinion). Radiant heat panel... from Animal Plastics, or what I and many others have done is buy the RHP from Pro Products and have it shipped to Animal Plastics, and they will install for you. However, Pro Products right now is also have some supply issues and are a few weeks backed up. Always good to call and ask.
There are many more.vwndors out there that sell PVC enclosures. Of note, however, in MY EXPERIENCE, the guy that says I can build it for you has for me always looked not-so-good. Cheaply made. The finishing touches you get with Animal Plastics, and I'm sure several other brands is a clean and professional finish on the product. Look extraordinary nice.
My 2 cents.