The old tube bass amps work well for guitar, in some conditions better than they do for bass. My favorite being the 5F6-A 4x10 bassman from 59. Today's bass amps are not so good for guitar being more of a full range amp/cab combo. I've actually used a G&K 2x10 bass combo for acoustic guitar a few times, but electric doesn't cut it.
The usual answer here is the Fender Bassman amp from it's tweed to Silverface versions.
I had a '64 6G6-B head that was an amazing guitar amp. My current '73 Bassman Ten with loosened negative feedback also serves great guitar tone for days. I have my eye on a '70 Bantam Bass combo. It's also a great guitar amp as the Bassman Ten is.
My old SWR Workingman's 12 and Mark Bass CMD121P are cool acoustic amps.
The Bassman RI is currently my #1.... Although it battles back and forth between it and my '63 Vibroverb RI.
The Bassman 50 just sounds like a huge Virbolux. I run it into a 2x10 cab and grin every time I turn it on.
1977 Ampeg V4B 100 watt tube bass head boosted by OCD with my friend Matt playing some modern style rock------- '70's Orange 4x12----- this vid was done shortly after I'd rebuilt this head and another similar 1975 Ampeg V4B head.