I know nothing about crocadilians. However, what I do know is how to build enclosures for exotic reptiles/amphibians. You want it nice, you want it cheap. Here is what you do. build your enclosure out of wood, plywood, whatever. if you want, go to a construction site, ask them for scraps, you would be surprised at what they are throwing away. I have built a ton or cages for friends out of new construction dumpsters. Anyway, forget the plexi glass. Go to one of your local big chain hardware/home products store. like a menards, home depot whatever. Go to their landscaping section. What your looking for is the rubber that people use to line the bottom of their backyard ponds. You buy some of that and you can mold it to the shape of your enclosure. been a while since I bought it, it probaly aint cheap however it will give you the freedom to create any shape living space you want and you won't need to worry about seams leaking which is sometimes what happens with plexiglass if you don't seal it correct. for the rest of the cage that water won't be a part of you can use the wood on all but the front or viewing side. for that side you could use a nice rubber coated wire screen or something.
one nice touch I have done with the rubber is after you have the rubber laid, to give it a really natural look is to purchase some non toxin super strong adhesive. Purchase some aquarium pebbles or collect your own and glue them to the rubber. Now you not only have a leak proof cage, but when you look down instead of seeing black rubber, which I think also looks good you see what appears to be the bottom of a stream. looks great, cheaper than plexi glass.
one other advantage of the rubber is that if you decide at any time to change your enclosure you just reshape the rubber the way you want it. Once you build a plexi glass cage your stuck with it. ofcourse you can't reuse the rubber if you've glued a ton of pebbles to it. but you get the idea