Hi-
I have several different species of bonsai and you are right I keep them all outside during the summer. We have experimented with several different species for my mom who likes to keep them inside mostly. We've had our best luck with a Chinese Privet. It grows and grows and is fairly forgiving in lower light conditions. She has kept hers indoors in a north facing window with a regular desk lamp (fluorescent bulb) in the winter and it is actually doing pretty well. While trees will greatly benefit from a summer spent outdoors, the Privet seems to be a good candidate for indoor growth. Of course, if you are going to have the money, time and space for an indoor grow light set up, you have tons of options.
Just my take on it. Good luck and have fun. Let us know what you decide on and post a pic of your new tree.