Basically, what Tanner said.
For most backpack applications, I would take a Nikon ED50 with a wide angle fixed eyepiece. Mine shows me 95+% of what my Ziess 65mm Diascope does.
But if you are really needing to count annuli rings on a sheep or judge the difference between a 165 and 180 inch mule deer a mile across a canyon, then you are going to have to carry the bigger scope in my experience. It's resolution and light transmission is just superior enough to make the difference.
I went back and read the OP. To directly answer the original question, my response is, " yes, there are compact spotters worth carrying." That said, if you're looking for a BEST recommendation, I would unequivocally say go 20-60x 60 or 65mm. Yes, I know you will not always NEED or be able to use the 60x but Tanner is 100% correct that you're better to have it than not. It's all about saving boot leather, time, and your body!
