Matt,
What about binoculars instead? The old standby night eyes were 7x50 and in my experience they are very good, albeit large for backpacking. But even 7x35 binos give an amazing boost to looking around in the dark... and as a bonus, they work great in the daytime as well... I've used gen 1 - 3 NVDs and you couldn't pay me to use gen 1 if I can possibly get my hands on gen 2 or 3.
8x40s don't offer any advantages over 7x35s - except that they are more often a higher quality bino with better optical components.
If bino size is a concern, I believe it would be inexpensive and simple to purchase an import 7x50 bino and tear it apart into one or two (depending on focusing mechanisms) monoculars. The cheap binos are not as "bright" (lower quality lens coatings) and are for sure not waterproof, but for the price... I imagine that they will do the jobs you mentioned quite well.
Regards,
Tom