You and about 500,000 other people have had this idea.
I have to repeat this speech nearly 20 times every year and I don't feel like doing it. Instead I will just hit key points.
The reason a Maid Cafe works is because the general premise is that it works for both males and females. It is welcoming and fun for everyone and the premise isn't sexual (although some people take it as that). It's very much about just enjoying your time, company, and most importantly comfort and joy.
A host club is nothing like this. Before you decide to continue on this idea please do your research on what a host club is. I won't cover it in detail, but I'll hit some basics.
Host clubs are very sexually oriented. The entire basis of a host/hostess(yes hostess clubs exist and they are more commonly known as cabaret clubs in the rest of the world). You go to one of these basically to get a person to be a temporary boyfriend. To flirt with you, to tell you how beautiful you are, and in some cases to try and sleep with you(off the clock of course). A good host is someone that can make someone believe that they love them. To trick the other person that they really do have feelings for them, without actually doing anything with them.
While I'm fully confident I could pull off a host club with a lot of work and finding the right guys, it's not something that should belong at Fanime. You're selling the idea of a sex. I've seen "host clubs" at different cons around the country, and they're a joke. First they're nothing like what a host club is... at all. Secondly, they guys fail. I mean this. Even the better looking guys fail at playing the role of a host, and out of the some odd 20 "hosts clubs"(or maid cafes with hosts, which do not belong together at all and I will rant on this for hours about how they are not even close to being in the same genre), not a single guy could pull it off.
Ouran itself downplays the idea of a host club, because you rarely actually see the host club itself. And when you do it's very snippety. All you see is each character flirting with a girl for a little bit using a charm point, and then it moves on.
So not even speaking about competition with the cafe, I'm dead serious in doing your research before you push this idea with staff (who will listen to you if you put in a legitimate proposal and idea of doing this).
But I'll tell you right now, if this idea gets more than "on the drawing board" I will hound whoever is doing it to make sure it is done correctly... and done correctly means it can't be at the con.