I think Blackstone Cherry has some really cool sounds on their latest record, imho for that kind of stuff,
a good classy sound is pretty cool, musically different, but I think the sound could fit: Richie Kotzen,
especially on the Family Reunion CD, listen to "fooled again", especially the parts with the Hammond, it
just works really well.
Ampwise it depends on how "sludgey" you want it
I am in love with Orange amps right now and Cornfords,
but a nice Plexi (especially with some fuzzy boost) could work really well, too, imho guitarsounds for stuff
like this depend more on the playing style.
Look how many different amps Down used for example, Kirk used his Randall with a Boost setup at first afaik,
used Hiwatts and Marshalls some time, now Orange.
Oh and I love Spiritual Beggars sound for stuff like this, too and another band that's a bit different but has
a similar vibe: Monster Magnet, just awesome!