I'm on a mission to get my kof collection complete, but I'm kinda sure there never was a kof2001 arrange... or was there?

No sir there wasn't.

thanks, and I've just come to the conclusion that there wasn't one for kof2002 either heh.

There was an AST for the PS2 port/collection of 99/2000/2001 though.

It didn't make the music any better but I always thought the NESTS theme was kind of cool.

I'm a bit late on the party, but for what it's worth: SNK before the bankruptcy bit, pretty much provided OSTs and ASTs for the vast majority of their game titles via Shin-Sekai Gakkyoku Zatsugidan......especially during the fighting game era. So for every KOF from 1994-2000, expect an Original and Arranged (and Drama if you're into that) Soundtrack for each title. After that, SNK went through some financial and company restructure. More notably, their musical group disbanded (Shin-Sekai), and as a result, hasn't consistently created the same soundtrack release pattern from years past:

KOF2001: As far as an official AST, never released (fine by me)
KOF2002: See 2K1
KOF2003: There's actually an OST and AST release, but is definitely not their best arranged work
KOF XI: This actually had both Original and Arranged Versions bundled into one package
KOF XII: This one is the great mystery to me...as it's the only title that I know of w/o a release of any kind. This is akin to Neo Geo Battle Coliseum. Some older threads led me to believe that the demise of Scitron (who had a hand is all KOF audio releases) had something to do with it, but don't quote me on it.
KOF XIII: The Original Soundtrack was just released by Team Entertainment last week and is in a 2 disc set. All songs on Disc 1 loop 3 times. The fate of an AST is unknown...but the cover does specify Original Sound Track.