Demonstrating the abilities of equipment, control systems, etc is of little use to a prospective customer.
They want to see how it will work and look in their home, and your home is the next best thing. Currently I do demonstrations from my home with central vac, cctv, projection and plasma home cinema and multi-room av. Punters often don't want everything I can do, but parts of it, and they can see from just a simple LCD in the kitchen with no visible wires and a do-all remote that you are the guy for them.
One manufacturer suggested I buy a house in town to fit out. Not really feasible for me but better than a shop or 'showroom'. Showhome sounds better though ;-).
Only problem is my wife feels she has to hide away and the place has to be TIDY and not smell like a takeaway! Difficult just after dinner.
Home cinema dem rooms are OK if you are mainly it to room remodels, etc. I feel you are limiting your market with them on their own. One couple came along and just weren't interested in it at all. Others love it but it's not what they came for specifically.
Also try and talk to interior design and furniture companies about the supply of goods, you may be able to strike up as good deal.
