Several options really -
If he loves Nishi, why not stay with Nishi?
N-Products limbs (What Nishizawa are now) can still be had from Italian dealers if you have the financial clout.
www.arcosportspigarelli.com (Flettenti) but they are 800+€
Cheaper option would be to check out some of the Dutch dealers for nice second hand stuff (Nishi were very popular in .NL)
http://www.dutch-archery.nl/ and check out the 2nd hand list.
Dutch Archery Specialist are also very reliable dealers - very knowledgable and won't sell you junk.
Both options (especially the first) would impress the hell out of me
Stretch