I'm like the Princess and pea when it comes to amps and EQ. I've tried nearly every amp on the market, and nothing ever quite pleases me. Fixed Q, semi-parametric EQ stages (SWR paragraphic, Genz Benz Shuttle Max, etc.) don't do the trick, either.
I was (and still am) very excited about the Streamliner, but it's still a bit bloated in the low end for my tastes, and so I went looking for a suitable external HPF or EQ.
This is all IMO and IME, but I found my answer in an Empress ParaEQ pedal. Most people feel that carrying a pedal and a wall wart is too complicated, or that it's better to have multiple amps. But at least in my case, the Empress turns out to be almost as easy to operate as a semi-parametric, and almost as powerful as a rack equalizer...