Under this CyberSchmooz section, there's a post by a lady named Jana about looking to sell her inventory from her bridal shop. You might also see if she might have some industry data to share.

Just a side note: there is a bridal planning shop in my small town (pop. 100K) that also offers wedding gown rental. My husband and I considered buying it, so we've talked with the owners recently. They said that other than the wedding planning fees, the gown rental portion of their business was very profitable. Especially since they offered rental dresses sizes going up to size 24. Our town has some very vuluptuous ladies. So the owners of this bridal shop marketed to this niche very nicely, offering them a good selection of dresses in their size at a rental rate that was about 1/4 the cost of purchasing the gown.