I was on a major quest for the same kind of combo requirements for a year or so. I had high hopes for the 500watt 2x12 GK combo but was really dissappointed by how anemic they were. In fact I was pretty disappointed with a whole lot of stuff I looked at . There were a lot of OK things out there but nothing to get excited about. The 2x10 Markbass was pretty nice at 500watts but it was a not a combo , which was alright with me, but I still felt I was comprimising somewhat.
Pilgrim got me all excited about the Genz Benz 6.0 Shuttle , and he was right. It took me a while to try one out but it was worth the wait. Not a combo but 600watts, lightweight and paired with a 2x12 and tweeter Avatar cab , I'm happy as a clam
. It was not what I was actually looking for but it turned out to be exactly what I wanted. I can't say enough good about the Genz Benz.
Rick