I'm thinking this is the opposite of what you want, right? If you can get the adapters you want with a byproduct of some throw-(give-)away pedals for $10, do it.

FWIW, I don't use adapters, but extenders (no change in size), I bought them off ebay from this guy username kindbro1. Search "stainless steel pedal extenders"; I see there are now at least three guys on ebay in this business. Anyways, I don't know that this will help you except to note that I use these extenders, the steel seems rock-solid to me, I have never noticed any problems.

I guess it is good that you should realize if you use an adapter that gives you an extension like this, the increased "Q-factor" will feel really weird (at least at first), and you may not like it. It is good for people like me though with duck feet (opposite of being pigeon-toed)