Hi, glass frogs are nice although you almost never see their interior, I dont keep this frogs but a cousin does and has 2 species Hyalinobatrachium talamancae and Cochranella albomaculata, they are easy to maintain in captivity if you give them plants hanging over a pond or stream. I think that the glass frogs all of you are planning to buy are so expensive for 2 things, 1) they are new to the hobbie (well, at least in the United States) and 2) their tadpoles take too much time to develop.
The Brian you are talking about is Brian Kubicki and he created the CRARC ( Costa Rican Amphibian Research Center) and also wrote the book about costa rican leaf frogs and costa rican glass frogs Costa Rican Amphibians
Any question you have on glass frogs just ask.