The good news is that I got a contract to write an article in which to discuss content-aware resizing (or rather, I got a contract for an article on performance tuning; I'll use the resizing algorithm as the sample).
The bad news is that the profiler I'll be discussing is native-code only, so it looks like I'll be writing my program in C++.
I would still like to do a managed-code version and I'll write my C++ with an eye towards portability, but unless I can figure out a simple seam-generation algorithm, I doubt that I'll have the time. Right now, I think Boykov-Veksler-Zabih graph-cutting is the answer as far as runtime efficiency, but it's not a trivial algorithm to implement. I spent last evening noodling around with other approaches that might not be as effective, but with which I'm more familiar; unfortunately, I didn't see anything to convince me they would work.