[MultipleParadox]

You could directly use a compact digital camera; Saw some people on youtube with a similar setup hunting small games with a Crosman Marauder; Nice and efficient.

You could get a relatively cheaper camera this way, and it hurts less if you something happens and it breaks

Also, you will most likely have to build a custom mount for this, which kind of defeat the purpose of going with a goPro or Contour, whose advantages are mostly mounting options

And I think the wide angle lens of those sport cams will cause more problem than anything when used on a scope like that, but I might be wrong on this. I think you might see a lot of your scope's edge with a 135+ degree lens