Linux-style window resizing
Zooom/2 is the closest thing I could find so far.
Sadly, it's discontinued and hasn't been actively worked on since 2011.  It is $20 shareware.
The functionality is pretty close, however it doesn't allow you to use the middle- and right- click buttons as modifiers, so it's not possible to mimic Linux functionality, but it's close enough.

The other major drawback is that it doesn't work with Photoshop :(  I suspect this is Apple's fault, however.