How good are you with spanners? I'm building (slowly) a commuter/tourer/advenrture bike out of an old hybrid that I got for nothing.
It will need quite a few spare parts - the whole drivetrain is very worn, although it works - and because I'm making it drop-bar it will also need bar end shifters and new brake levers - but doing all that is cheaper than buying a new bike, and it means I can get exactly what I want. The frame can take tyres up to 50mm.
I will end up with a 700c drop-bar bike with 38c tyres (although it can have any from 23mm to 50mm if I swap the wheeels) so it will be nice and comfy but will have the flexibility of the drops. I do own a mountian bike but I don't do trails of anything madly muddy - I don't see how that can be fun, but each to their own! What I hope though is that the finished bike will be useable as a commuter, for longer rides (it has rack mounts) and for mild off-roading, so I can go up into the Peaks on road and then explore a bit. Basically it's going to be a bit
Salsa Fargo-ish - heavier and less well-specced, obviously, but also £1300 cheaper.