Just wondering why a 'rehearsal studio' would need a 100 watt guitar amp. The loudest guitarist in my band has a 30 watt combo for stage use and the other one uses a 16 watt tiny terror - both plenty loud enough for any pub gig so way over the top for a studio.
That said, until recently I've been lugging my stage rig to rehearsals at our normal studio but I've just invested in an Eden E210C - 350watts 2X10 .
If you want an idea of what not to put in a rehearsal room, check out the sub station in rosyth. Loads of tired second or third hand crap in there to avoid.