Thanks for the feedback! Yes, I'm talking about using two of them. That's what I do now, setting one amp on either side of the drums. The KC-350s have a stereo link so I only have to plug my instruments into whichever amp is closest. None of the small PAs offer this feature, so I'll need some long signal cables. And a mixer.
Jeff, I was just looking at those Turbosound speakers (the iQ12) but was put off by their B.S. claim of 2500W of power. At 46.4 lb they're pretty heavy. Plus they're tainted by having the same parent company as Behringer. Still, they're $200 less than the QSCs so that's a plus. The Yamahas you suggested are also on my list, being cheaper and lighter than the QSCs. Plus I've heard them before and they sound fine.
The EVs were not on my radar, though, so thanks for that link.
As for 1000W a side being overkill, that may indeed be true (assuming those numbers are honest), but having headroom never hurts. Heck, I've got 800W on my frickin' studio monitors! I'll tell you what does hurt, though, and that's lifting those Rolands into the van at 2:00 AM. The Yamahas are considerably lighter than my current amplifiers.
Sir William, are you doing a solo act with the K-12's? That does seem like overkill. But encouraging. I have two musical enterprises, a 5-piece rock and blues band that gets pretty loud, and a quiet duo that never gets loud. Sounds like the K-12s might fit both situations well.
The KC-350s have a 4-channel stereo mixer built in, alleviating the need for a separate mixer. Which also means I'll have to get a small mixer. That choice is easy, as I'm going with my favorite small-mixer brand, Yamaha. This one's bare-bones but has all the features I need.