Julie,
my "studio" is in my office which just happens to be my old living room. It's 20 feet long with a 12 foot ceiling and gives me just enough room for my backdrop, lights and a teeny bit of room for me to maneuver.

The storage area sounds ideal. Keep in mind that most of what you'll be shooting will be outside or on location so having a travelling studio setup is better than having a setup you bring clients to. My entire show setup fits in a single case and can be set up in less than 15 minutes.

Jim