Yeah. A steam client would be nice. I don't use it all too often honestly, but it can always come in handy, and the more apps available, the better.
A protocol for conversations would be nice, but a full fledged client would be good as well.
Have you considered e-mailing Valve? From my (limited) experience they seem to be cool guys, and would most likely have no problems and might even help with some of the work.
There are about another 20 votes from our website and Facebook page. Certainly not that much, but our website doesn't reach that many users yet.
Compared to the average number of how many users usually participate at our Facebook page votings (small number compared to visitors), about 15% of them voted for a Steam Client.
I think the result is ok for a niche application - it's always hard to get people's attention for apps if its not WhatsApp or Shazam