I'd like to list the proper noun sense of this term now, but delay any decision until we finish CFI refinement for proper nouns.
Questionable sense: “Italian violin maker Nicolò Amati in Cremona; taught the craft to Guarneri and Stradivari (1596-1684).” As a proper noun, it is mislocated, but even ignoring that, it may fail pass WT:CFI with refined proper noun criteria. Rod (A. Smith) 22:59, 8 August 2007 (UTC)
The sense in question should certainly be at Amati if kept (as you note). I would say this passes CFI as a noun signifying "a violin made by a member of the Amati family"; see w:Amati and b.g.c. results for 'an Amati'. I can't see any indication that it is used overwhelmingly to refer to Nicolo or his work, though. -- Visviva 02:49, 9 August 2007 (UTC)