I just go off road on my track frame! As long as the tyres are tough enough I don't find a lot of difference between a track frame and a cyclocross frame in use. Clearly this is for pleasure and I am not racing.
Mud clearance could be an issue if you ran brakes I suppose but my riding is fireroad and hard pack singletrack so mud is not usually much of an issue.
Just allows me to ride off road without having to need a specific bike and that suits me.
So you run a brakeless track bike off road? I'm looking to ride some off road at the moment but only have a road bike and a track bike. I suppose I could fit 25mm tires on the track frame, but can't see anything other than smooth hard pack being a possibility.