You know, if I was starting out from scratch as far as my batteries go. I think I would be tempted to put one of those programmable voltage regulators in each model, and then buy 2 or 3 lipos for receiver packs and just pop them into whatever I was going to fly that day.. I have had very good luck with Nicads over the years, but having about 15-20 models .. I think I would go to a few new batteries I could move over replacing 20 nicads...
just a thought.