Second the KX3 recommendation. K3 for the home shack, and KX3 for portable, stationary mobile, etc.
When 6 meters is open, it is open and often you don't need much in the way of power to work just about all you can hear...bigger antennas and higher power allow you to work stations at the end of the openings, often when most of us are no longer hearing anything.
That said, if you want a 6 mtr only rig, check out the MFJ 9406. For such a simple rig, and often found used for around $200 you can't beat it. It was my first 6 mtr rig, and as I said, when the band is open, you can work 'em with this little box. I kept it for years and loaned it to others when they wanted to get their feet wet on 6!. Combined with a simple loop or homebrew hard dipole, it was a lot of fun.