Re: Rack EQ? good or bad?
Rather than a single-setting unit, I'd suggest a programmable one, even if it was a multi-FX and all you ever used was the EQ. The Digitech TSR-12 is a nice unit, and features graphic and parametric eqs of varying bands and sweepable freqs. The programmability lets you set up similar patches for different guitars so they work well in various rooms, with various amps, and various other tonal factors. As was stated earlier, you're not going to coax Tele tones from a Les Paul and vice-versa through EQ - you'd want a Variax for that anyway - but it'll keep the LP from being to boomy and the Tele from being too twangy. They'll still sound like they're supposed to, you'll just have more control over their room interaction.
I have used the TSR-12 in the loop of an amp (Peavey Transtube 112) but I can't speak to the Line vs Instrument requirement of the TSR or remember the persuasion of that amp's loop. These days it lives in my rack, with an ADA MP-1 running into it for tone-shaping EQ and effects.
Lugging around a 2-space Anvil or SKB rack (the TSR-12 is 1-space) is not all that extra hassle, and if the rack case is large enough, it could pull double-duty for extra cables and mics if needed.
At one point I had a padded rack bag that held my MP-1, TSR-12, a GSP-21 and its pedalboard for MIDI control of the MP+TSR combo, my volume and wah pedals, my wireless receiver, power strip, and the cords. I'd get to the gig, unzip the bottom and dump pedals and cables out, plug my strip into the existing strip, run the cables to the amp, then flip it over to get to the front panels. The rack units stayed connected at all times, as did the foot controller, wireless receiver, and wah and volume. The cable to the receiver was long enough to be used as the main guitar cable if the transmitter died during a gig, or if I started picking up passing truck CB radios.
The bag also had a pocket on the front for extra cables and mics, and a shoulder strap. Lugging it around wasn't much of a chore; I walked in with the bag on my shoulder, combo in one hand, guitar case in the other. They make 2-guitar heavily-padded guitar bags, as well, if you take a spare with you. Or you can just carry two SKB-style cases in one hand, holding both handles (or strap the cases together for transport).