I found a post where a guy name poorboys bikes made his own drop-out extensions that look nice and are bolt-ons. He doesn't sell them and it looks like he might not be around here anymore. I don't know.
I'm sure they are one a kind but,this may give you a good idea what to do when designing something specific for your bike.
Post#4 has the picture you'll be needing
I'll keep a look out for more in my bookmarked bike parts supplier lists.
Take er easy buddy... Hope to see you again someday in the not too distant future.