thx

sounds to me like the kind of place where a casual thief is pretty detterred...but a pro, no matter what will get what he/she/they want(s)....so make sure you have good insurance on both the bike itself and rental insurance on the unit for anything you have stored in there and don't worry so much.

You should try chaining the bikes together since you state there are several of them.  It wont stop a pro (few things would) but 1-2 chains crisscrossed btwn the bikes and then anchored to the ground would require the avg thief to cut through a lot of case hardened steel in order to get your bikes out.

The reason that I say this is because I heard a story before of a guy with 3-4 bikes parked in storage and an attempt at stealing his bikes was foiled due to the thieves not being able to get through the chains he strung through all his bikes.  They didnt have to the tools to get through the chains and couldnt pick up all the bikes at the same time.  Took them long enough that someone noticed and called the cops.

I would try to make sure that they can't get in to the garage.Once they were in they would have all the time and privacy they need to strip parts,even if the bikes are all chained and locked together.