Which basic amps can drive 1 ohm loads ?

The older Krells (KSA 80, 100, 200 and References, as well as their monoblock versions) were about your only choice back when Apogee was in business, a major reason they used to be demo'd together. Would expect them to still sound good as a combo. Don't know what's available now, but I'd expect a pure class A design might fill the bill (Gryphon?). You might want to check the archives for a link to the Apogee users group website, I'm sure they'd have plenty of suggestions.

McIntosh has performance graphs for most of its recent amps that show total stability at 1 ohm.

However, it also depends on the volume you wish to listen at since the power is to the square of voltage (P=V^2/R). Most amps will do it at low volume but then they will either overheat (surprising how many designs are inadequately cooled) or clip heavily at higher levels. It's hard to answer your question directly. I don't know of any amps that will rock hard at 1 ohm for extended periods. Need to look at the impedance graph of your speakers because the minimum may only happen at one point.

The InnerSound ESL amp will drive one-ohm loads comfortably, sounds very good, and has plenty of power and punch...

I had a KSA100 for a while but it blew transistors so I got rid of it.