Does anyone out there know of a service for the repair of mmc4 stylus? I am aware that replacements can be obtained from the U.S. as made by Soundsmith, but is there any way of stylus refurbishment?

Yes. Suggest you read this

http://forum.beoworld.org/forums/t/30106.aspx

Soundsmith in NE US retips (just about anything I think) as well as sells new products.  I have a new Soundsmith and like it very much.  (I believe the cost for retipping is given on the web site.)

Modular Electronics in Atlanta, Georgia area retips MMCx to MMC4 specs as long as the only thing wrong with the cartridge is a worn stylus or broken cantilever.  I have a retipped MMC4 from Modular Electronics and like it very much.  (If I remember correctly, I paid $100 for the retipping.)

Axel in Germany (search this forum for "Axel") is very highly thought of on this forum though I have no personal experience.