NOTE: This post is about new KITS, and METAL parts.
The larger centerband for the slimline is a totally different issue.
First of all, it is only one small part of a kit, and a simple one to make at that. I think a very small investment would give the supplier a new kit.
Second, there are large centerbands already. One comes with the PSI comfort pen, which is just a slimline with the larger centerband, AND a piece of rubber that most of us don't use. A band like this could be sold separately, or the kit offered without the rubber part at a lower price, or as an option to the slimline.
Third, since it can be made in a lathe, maybe someone with the proper equipment can make some nice centerbands and sell them. These would probably be high end centerbands with all the bells and whistles, and cost more than the imported parts.
PLEASE, don't tell me that I can make my own centerbands, or omit them. I already KNOW that, and have been doing it for a couple years. We are talking about METAL, and possibly plated. OK?