Well, there's a marshall TSL 6-series head out there... don't remember the number, but it's basically the amp you're looking at now, minus the speaker.
Also, i'm personally a big Mesa fan, and inches away from picking up a Single Recto right now... Pretty cool head, great "metal" crunch tone but the vintage mode on the distortion channel is a sweet solo voice, too, and while it's only got 2 channels, it's got a footswitchable "solo" master boost, so while you can't set it for different "tones," you can still have a way to let your solos cut out a bit more in the mix. the really cool thing is, it's not channel specific, so you can get a boosted clean tone AND a boosted distorted. rock!
the full-size Nomad 45 head might also be worth exploring.
Also, there's a Soldano 50-watter that's been making a bit of a stir on this page recently, and you can set a Legacy down to 50 watts... And if you're really hung up on 3 channels, if you pull the two center tubes from a Dual recto, it effectively cuts the power in half, and a friend of mine's VERY happy with his H&K Triamp...
So really, i was so general here i didn't help you at all. oh well.