sand boas wouldn't need a tank that large.
To be honest glass tanks are a poor choice for most reptiles except those that require alot of water (ie semi aquatic or full aquatic turtles, amphibians etc.) Glass is a poor insulator and it is hard to keep humidity and heat balanced.
From all sounds of things, your BRB setup was way too hot and it overheated and died. Too much heat can quickly kill most reptiles, especially if they don't' have a cool place to retreat to. Though I don't have the large collections as other BRB keepers do, I have found it very easy to keep BRB's from babies to adults for years in large plastic clear storage bins. Easy to clean, easy to maintain a consistent heat and humidity level.
Glass tanks can be used for snakes but you just have to be aware of their limitations and weak points. An all screen lid allows for heat and moisture to escape quickly. Lamps dry out the air if you are using that for light or heat. Covering the screen with plexi glass or even saran wrap and using under tank heaters on only one third of the bottom of the tank (controlled with a thermostat) and taking regular measurements of the surface temperature above the heating pad and in the cool section will allow you to control the environment better. For humidity providing a large enough water dish for the snake to soak in and humid hides will ensure proper hydration.
As you indicated you had bad experiences with several species of snakes, I think it would be better to do more research on the species you have currently and ask questions in the appropriate forums for advice on your current setup and interactions with your snakes. Most experienced keepers of Burmese pythons and retics I have talked with or read about had no problems handling even problematic snakes and easily turned them from monsters into calm snakes, mostly because they had a deep understanding of the snake's habits and needs.
Ball pythons definitely are finicky eaters but can easily become regular eaters with the proper setup. They like to feel secure which means plenty of tight fitting hides and good temperatures.
I have been keeping ball pythons, corn snakes, rat snakes and Brazilian rainbow boas for some time, the corn snakes the longest. I researched each species before I bought them and I still research them to learn new techniques and improvements on old ones. Even my lizards I researched long before I bought them and still keep as up to date on new discoveries and techniques, always looking for the best way to keep my animals healthy.
You may find corn snakes passe and boring because nearly everyone has one but there is a good reason why they are still one of the most common pet snakes kept. They are easy to care for and very fault tolerant.
If you really want to use the tank you have for your next pet, you could look into bearded dragons. A 50 gallon breeder is about the same size as the minimal size recommended for an adult dragon. You will need to get light fixtures for a UVB bulb and heat lamp, plus accurate thermometers to measure both surface and air temps to ensure you have a proper hot spot for basking (95-120F, 105F is a good middle point to aim for, this is surface temp. For ambient in the basking end of the cage, you want low 90's F) Cool end should be 75-80F air temperature during the day and normal room temperature at night (65F-70F).
Bearded dragons do require more daily care than a snake, especially if bought as babies. Research more about them if you think you may like a lizard. All lizards require far more feedings than snakes and most often much more variety of food items than snakes.
I don't know alot about the care requirements of blood pythons but I do know they are not big eaters. Yes, they will eat anything and pretty much every time you offer food but they don't require weekly feedings, many in captivity are over weight due to too much feeding. Captive breed bloods are not as difficult to work with as wild caught, which can be very prone to striking and biting. The blood python forum certainly will have more care information available than I know off hand.
But being very girthy snakes, your glass tank may not have the width to ensure their comfort once full grown. It may very well be more feasible for you to sell that big glass tank and build or buy a tank designed more for snakes than fish. (often the height in fish tanks is wasted for snakes, unless you are getting a semi arboreal species).
There are also various rat snake species that reach the 6 foot mark or longer, like tiger rats, black rats and I think some of the Asian species. There are also gopher snakes and bull snakes which get fairly large. I think some pine snakes reach the 6 foot mark as well, but I am not sure. All these snakes do have their own husbandry requirements which will need to be researched as well.
-----
PHLdyPayne