Mr Aqua makes frameless tank that are a lot cheaper than most other brands. They are made from thick glass sealed together with silicone. This is the 5 gallon which is 10 by ten inches at the base and 12 inches high and has a front with a vertical bow. Shown here with a submersible heater, Hagen submersible filter and Tom light.
I am using this one to house three dwarf orange crayfish and some red cherry shrimp. The tank seems to be a good quality for the price and displays well. Now I just need to get some plants to grow up enough to conceal the filter a bit....
Dwarf Orange Crayfish are referred to as CPOs. The two main things to keep in mind are their need for oxygenated water and that they can be aggressive.
You can use an air-pump, line and air-stone. Personally I prefer a Hagen submersible filter, it injects air directly into the outflow. This helps recreate the basic environment required for a species adapted for life in a river.
CPOs seem to vary greatly in aggressiveness but it is wise to give then lots of hiding places and not overstock. I would suggest a baseline of three gallos for obe, and at least a gallon for each additional crayfish.