I have a similar impression like Paradog. A Gnutella client with all the proposed extensions is quite a big project that can't be handled by a single guy anyway.

Perhaps it would be better to contribute to an already existing client instead of reinventing the wheel. I would think that there are already clients in preparation for C# (I know none, but that doesn't mean there aren't any).

It'd rather have a couple of full-featured clients for the different operation systems than have a lot of different clients that don't implement all of the features or whose projects are stopped after some time. And we already have quite a couple of clients out there and only some of them are really good and up-to-date in respect to the features proposed on the Gnutella RFC site.

And why the heck should it be C# anyway?