You must deal with the issue of ownership, in writing. You should retain the right to take back your products, and you should include a clause that allows you to enter the property in order to do so. Ownership should be clear in the event of the other company folding.
You must also make sure that your products are insured while being looked after by other people... and what happens if they get damaged while on loan. While it'd be nice to treat damaged items as sold items it may be too punative, .. you might have to relax it, to damage caused by negligience, etc etc.. genuine accidents may have to be allowed for, .. but not fire or theft, this should be insured against.