In my experience, a true ex-hire or former rental seller on ebay will have odd sizes or advertise some goods as something like "costume quality" and even mention damage. It is normally the cheaply made knock-off sellers that have all sizes available on a regular basis.

When my wife and I got married I picked up a former rental tuxedo (this was before I purchased a kilt, or I would have worn a kilt in the wedding) from an actual tuxedo rental company in the US for $30 US off ebay. I checked the seller information and found an actual business address and website for the seller. Most of what they were selling were mildly damaged or sizes that people don't rent as often. As I wear a 42L and fit best in the slimmer Euro style over the wider US style I was able to find what I was looking for in good condition in a few weeks of searching.

I have searched from time to time and have not yet found any high quality ex-hire kilt jackets in my size. I sure there are some out there, yet I would need to be looking close to when they post the jacket for sale.