Living room system: class A or AB amps?

Those speakers are tremendous.  A/B gear is going to run a lot cooler than class A.  I run low wattage tube amps and they run absurdly hot and warm my room.  Big, class A, SS amps are going to generate a ton of heat.

Not going to be as cool as Class D, but check out the AVM Ovation 8.3 mono's.  They will deliver plenty of power for any speaker and are extremely natural sounding. I have a pair that were damaged in shipping around if you want to hear them.  They are jaw droppingly good and I think will be an interesting alternative to Pass.  

Another interesting option would be VTL Siegfried IIs.  Again, tons of power and tonally VTL would be a good match. 

Gryphon and Pass are fine options and are certainly great sounding.  Good resale with both.  The other one I can't believe hasn't been mentioned is Naim.  It is the sister company and it sounds amazing. 
 

Krell and your done!
Good luck with your quest.

@millercarbon

Maybe I should have chosen different words, and leave "class" out of the equation.

Little kids, pets and a living room environment may require a rack or cabinet. For these customers, size, weight, heat and safety become real factors. Nobody wants their toddler to fall face forward into a bed of sharp heat sinks. They may choose D'Agostino Momentum monoblocks over Pass Labs XS300. Because they both sound great but the Momentums run cooler and are easier to fit into a cabinet. Safer and more suitable in a living room.
You may cringe because these restrictions mean they will never hear the system's full potential. You may find it a waste of money. But why not if you have the budget to get awesome speakers and high-end components? Yes, the restrictions suck. But it beats defaulting to a $3,000 home cinema set. 

Best Class A: I do like the warmth and natural sound of Wavac, Ear Yoshino and Metronome Technologie.