Ok here’s what I have found. I put every possible word and sentence into google to try and find them but had no luck. It was only when I searched leather body harnesses it led to harnesses that are used for fashion to harnesses that are used for bondage (ironically this was probably the inspiration for Mötley Crüe’s ones as they look very similar). So if you are willing enough to go on some of those bondage websites you could probably find some that look like Mötley Crüe wore them (I only had a quick look at what they had on the homepage, that was enough for me). If not there are a couple of websites which have very simple harnesses but don’t really look like Mötley Crüe’s ones.
I hope I helped a bit!