Yes it'll be for use at home, purely for my own enjoyment at neighbour friendly volume levels.
I don't have a budget as such. From what I've read and heard (online) a lot of valve amps sound at their best when they're pushed fairly hard at the output end. If such a thing existed to achieve that tone but at living room volume and all the way up to on stage without changing the tone I'd be happy to pay for that. Say a B15, if I could that to perform at low volumes I'd probably get one, but I'd don't think it's achievable. I'm happy to be proved wrong though!
Thanks for the WEM info. I've seen a few on EBay and like you say they can be picked up at reasonable prices. How are they at low volumes?