This is one of these things that's been running on a background thread in my brain for about a year, I have never seen a good example of how to do this but it just seems handy (I don't know what for but it 'feels' handy). Anyway, in the Codeproject mail thingy today this article was hiding at the bottom. Now, one of the comments mentions a way to do this in C# - going to have to try to get this working!
UPDATE: I almost have this working (just a very slight size issue right now) the handiest info is this discussion