Buddha
For what it's worth, I had the same requirement (for summer shorts as comfortable as my winter Bikesters). Having found nothing as light, simple and comfortable in the shops I took the scissors to my Bikesters on Monday (I'll buy some more Bikesters for next winter).
Results: first, very easy to cut, cuts very clean (with big tailor's scissors) and after a few days at least, doesn't seem to fray even with no treatment of the bare ends. And it feels like you'd expect - very comfortable. So I'm a happy camper (although wife isn't sure about the style points...).
Enjoy the summer - get those knees out!
Skinnes