Varonha Frameworks winter bike / FW Evans 650b conversion rat bike fun

What are my options for:

• cheapish / pub level, steel frame, preferably secondhand.
  
• enough room for 40mm tyres plus guards
  
• front and rear rack mounts
  
• disc brakes (I would quite like to be able to run 650b with fatter tyres as and when)
  
• will take most of what I have left from the wreckage.... is there even a 1" threaded option, or is that a dream too far?!
  
  

Basically a beater / rando / gravel bike thing for leaving outside the pub, going on touring holidays, and exploring a bit of off-road.

Throw suggestions at me, I'm all ears.