Wasabi,
First off, let me say, masterful work.  I am impressed!
However I do have a question; I have tried running a build of the console application application (after changing the config to point to my own slush account, of course).  It works, keeping a steady 100-140MH/s on a GPU miner.  However, I am not seeing any activity being registered at slush; this makes me think my machine is either wasting work or is still working for you despite the change in the configuration.
Now, I tried changing to a dummy config and it did no work, which eliminates the second, I believe, so I don't think you're actually cheating me.
But I am curious as to why none of these millions of hashes is being accepted?
I really want this to work for a variety of reasons.  But I'm wondering if hashing through .NET might just be a dead end.
T