You guys are silly. I hosted a video game convention in 1997 that was successful enough that others planned their own the following years, even in different countries!
I you want to have a party, sometimes if you can't make it there you have to throw one yourself!
With 140 guests in the forums right now, I am sure that if someone took the time to throw a party, you'd get guests. I also think suggestion is a bit abrupt. Nice idea, but too short notice. If you wanted one this summer, and you wanted a decent turn out, you need to plan this more than two months ahead. As you can see in this thread, a lot of people... already had plans!
Now, I am not sure what you guys have done or will do at a DF party (aside from play DF), but something like comic con or wizard world or some gaming convention like that is large enough to be of interest for a lot of people, and anyone dressing up as a dwarf would fit right in with the slave Leia's. There also will be other things to do if everyone but yourself turns out to be, well, a real geeky dwarf.
When I hosted my convention, I paid for the hotel conference room costs out of pocket and charged a modest admission fee. Discounts were provided to people that signed up early, and I had free trinkets to hand out. Getting people to sign up early let me know just how much interest there was. I also brought some video game systems and tvs. Other people brought their tvs and game consoles and what have you, and it lasted two or three days. I had game developers come in to show off new games and some people brought in rare prototypes of older games. I probably had between 40-60 people show up, not including my friends who were forced to attend or I would Hammer them. About 15 of them sent in the bucks. I charged at the door but after a while I decided I couldn't care less and stopped taking attendance since I was missing out on everything.
You get the idea. This is a little more focused, since it's essentially a single player game... so other things need to be planned, I think... card games, dnd, online gaming, something. You also need to be prepared for people to come with someone that might not be entirely interested, so its important to have Something for them to do, or the interested person might end up getting the guilt trip to leave early.