I always hear praise for the Spark - does it do the same dirt on a solid state amp? I won't be pushing tubes, so if it's truly a booster, I doubt it will work as well for me.Two suggestions, different price points:
1) TC Electronic Spark Booster. Not the "mini" version, but the full-sized one with bass and treble knobs. Inexpensive, versatile (I have two of them), and does the barely-there-low-gain thing exceedingly well. Pretty quiet, too. And as said, inexpensive; I paid $50 each, new.
2) Broughton SV-Pre. Does the full range of SVT-style dirt, but IMO works best in the low-gain area. Volume to the max, Gain as low as possible, enjoy. Bit pricey and hard to find on the used market, though.
Honorable mention: Damnation Audio MBD-1 or -2. Does the low-gain thing well, and comes with nice sound shaping options like the Deep dial and a dry blend. But personally I like it better when pushed, I even use the MBD-2's +20dB switch, so … yeah. Honorable mention.
And funny you mention the MBD-2 - that is one of my front runners right now, and I just tried the MBD-1 and am really loving it. Was wondering about the 2 vs 1 comparison, as I definitely want the smaller option if they do the same tones.
