G12H is middy, but has a midscoop gap at some very audible frequency, and also a lot more bass and a more aggressive top
very different from a G12M
maybe a weber 50w ceramic silver bell or a scumback 65w M75?
eminence makes some cheaper ones like the private jack and the GB12, but they don't sound like celestions at all
I had a quad of the regular G12M's, pair of 70's rola G12M with 55 hz bass cones and five V30's... also the neodymium version of the v30, which was actually pretty good, although somehow unique sounding
right now I have a pair of scumback H75's, which is still pretty close to a regular celestion G12H, but a bit middier and rounder, and some boutique MG music Black Dog speakers
the MG Black Dog is supposedly a G12M clone, but it doesn't sound like one
mine is 50w, and the magnet and casing are the same used by Weber on the Silver Bell
paper layered bobbins and the same cone as the G12M, but it's much fatter and louder than a G12M and has a rounder and cleaner top
I love these speakers and they are very easy to deal for every situation (home, band practice, gigs, and specially recordings), BUT they won't deliver the aggressive celestion snarl
if you can find the G12-65 for cheap, go for it, but if you can only find the heritage expensive version, get a scumback M75 instead