Thanks for the welcome. Incidentally, we happen to have the same first name. Nice job.
Regarding the plastic 5 gallon tanks: I think you are referring to the Eclipse brand tanks or their knock-offs. I happen to own a hex version and I'm really quite happy with it as a little fish tank. However, I'm looking for something a little more sturdy given my new living conditions (grad school).
I would love one of the small custom tanks I see some companies offering, but I can't seem to part with $80-100 to buy one. So, I'm thinking there has to be something out there designed to hold a liquid, pretty sturdy, made of acrylic and mass produced so that it's pretty cheap. I just haven't found it yet...