Montana Vintage Arms offers Pope and Winchester reproduction globe sights with dovetails other than Lyman! They will even make custom size dovetails. You can have a dovetailed globe or a dovetailed base and a clamp on globe (but is higher off the bore). These both use brand specific inserts with many configurations available. (I have a Winchester style globe on my Shiloh Sharps with a veneer rear.)

Anschutz uses a larger and metric dovetail that may be of use. Champion Shooters Supply (800-821-4867) stocks these and many of the Lyman's.

Lyman used to make none cut dovetails on globes and you cut the size you need. I don't believe these are currently in production , but there may be old stock around.

Ivan