well, i'm using a Monarchy SM-70... soon to be upgraded to the Pro version. it's 25wpc @ 8ohms... so, it's not a bad match in power ratings with the k1000. it's the lowest powered pure class A solid state amp i could find anyway. if you call akg, they will tell you only to use class A amps...
...but honestly, with this combo, the sound is a bit harsh. but there's a good reason... this amp outputs full power all the way to 20khz!... forget finding a tube amp that even comes close. i've already had several converstaions with Mr. Poon (owner and chief engineer)... and he insists that even at 120 ohms, the response is flat all the way to 20khz.
so... right now i'm looking to buy some ASL Wave 8's to compare with. but if you're interested in the pure truth of the music, the combination of the AKG K1000's ability to sound like super-speakers, and the ultra-flat response of solid state amps will not hide any details, good or bad.
...so, if you're going with solid state, i don't think you can find a better amp for the k1000 than the sm-70, at any price. (there aren't many in this power range.)... but if you're just looking for a nice listening experience, you might want to avoid solid-state amps--tubes which would be more flattering... it's like girls' make-up. ...makes girls pretty, and many just don't look right without it... but man... when you wake up with one in the morning.........
i'd rather just listen to music for what it is.