Wow where did you find a 48x24x16 for $409? That's an insanely high price. I can get an AP T-13 48x30x18 for $410 shipped. Now a Boaphile 422d which is 48x24x17.5 is $419 shipped but imo those are too expensive. The good thing about them is you can add onto them as needed so you can make a 8' cage but again the price on them is expensive. Ed from Constrictors NW is going to start up with Pro-Line cages again in April and I got a 48x24x14 from him for $250 shipped. Now sure if you look at stuff like Showcase cages or Vision cages, those are expensive which is why I recommended AP cages to the OP as they get very good reviews and people love them plus their prices are very reasonable. Heck the T-10 48x24x15 is $250 shipped. The only downside is it seems to take about 3 months to get the cages once you place the order.
Also glass is a very poor insulator yet weighs a ton. Why do you think most new houses use double or triple paned windows now. Its to give air pockets between the panes which act as insulation. Single paned windows or tanks in this case bleed heat. For me, I clearly see a lot more advantages with using PVC or HDPE cages but to each their own I guess. I think you are the first person I have ever met who actually likes glass tanks over PVC or HDPE cages or I should say advocates for them. I will say they make good temporary homes but like I said, I wouldn't want to use one to house a 6-10' snake in.