Pass Labs INT-25 or equivalent in another brand

Luxman 590 would be A, 509 and 507 class A/B

I wonder if anyone has a list of A/B amps that stay in Class A for long enough to really erase the difference btw A and A/B?

I think some of the Accuphase integrateds are class A up to a wattage that would drive those Heresy IVs pretty loudly.  Prices in the States are a bit steep, though.

I believe CODA makes an integrated that runs into class A for a higher output.

http://www.coda-continuum.com/product/index.php

The Luxman L-509x stays in Class A for the first 6 watts (8 ohm load) before going A/B to its rated output.  The L-507 probably the same.