Which Amp for uppermost freq' in tri-amped setup?

I need to choose an amp for the upper frequency range in
my tri-amped system, and I may be making this decision more
complex than I need to. Crossover frequencies will be 150Hz
and about 4000Hz. I have two Marchand crossovers (XM-9),
two NAD 2600a amps for the woofers, and a Linn 5105 amp
for the mids. (I may only use one of the NAD's, but could
run two in mono if desired.) So,the amp requirements for
the top end should be easy to satisfy, no? High wattage
or current flow should not be necessary. I would think
low distortion up to, say, 50KHz should be a more important spec.
I'm leaning toward a Linn LK85. I know this is an
unusual question; I sincerely welcome your suggestions and
comments.