Tweed is pretty damned sweet on my Roadster, too, though I find that unless I'm playing bluesy lead stuff or Jimi-esq chording I almost always stay on Clean or Fat. That said, hate to fuel the GAS, but the Roadster DOES have that 4th channel.
My problem with the Mark-V is the the way the modes are laid out - there's probably an engineering reason for this, but they're laid out by level of gain more than they are by function. You've got one clean channel, which is cool, and then a second channel with three lower gain modes - "Edge," "Crunch," and "Mark I", followed by a third channel with three higher gain modes, "Mark-IV, Mark-IIC+, and "Extreme."
The problem for me is that in an ideal situation I'd be using Mark-IV for leads and either IIC+ or Extreme for rhythm, but I can't because they're on the same channel. Mark I isn't bad and would do in a pinch, especially with a nip and cut here and there from the graphic EQ, but it's far from ideal.
I had the same problem with my old Nomad, too - Channel 2 was the "medium gain" channel, and neither Vintage nor Modern really 100% did it for me for soloing. Channel 3 Vintage, however, was
perfect. Similarly, 3 Modern was an awesome rhythm sound. But, since they were on the same channel, I had to choose one or the other and then solo with it with the volume boost. It worked, but again it wasn't ideal.
the Roadster is the first Mesa I've owned where the layout is perfect for me right out of the box - 3 Vintage and 3 Modern work almost equally well for lead for me (it's kind of a mood thing, they're really quite similar; a surprisingly smooth, articulate Mark-like lead voice), and then 4 Modern is perfect for rhythm. That leaves me 1 and 2 for clean to crunchy sounds, plus a footswitchable solo boost if I wanted to take a lead with any of the channels.