Maybe someone with gasser experience can help, but I've seen them down to the 1.2-1.4 ci range. (Starting to become VERY tempting for me also!)

I would not recommend going to something this large at first, with the thought that it probably will crash at least once. Gassers are larger, ($$$), and also need more/larger servos, yet more money to burn if you crash it.

Also, you mentioned using your existing radio equipment in future planes. Although a good concept, it is usually easier to get another flight pack, this way any of the planes are flyable at any time.