If you'd like help running a roleplay you should try posting in the roleplay discussion thread. Your original post is below so you can copy and paste it if you wish.
Spoiler:
I want to start an RP, and I hear that this is where I should write my proposal. If what I have in mind already has been done, please let me know. Otherwise...
What I'm aiming for is basically the style of a regular forum/chatroom/[insert correct terminology here] where people post under the context of being average trainers in the pokemon world. We talk about raising pokemon, recent battles, that jerk at school/college/work who you think mistreats his pokemon-- real-life as though pokemon were real. There would be no real plots, as the nature of this doesn't really mesh with such a thing-- after all, life doesn't have a plot. Posters would have characters, although they probably wouldn't have much behind them other than personalities-- since this is based off of a chatroom, there isn't really any need to see people face-to-face.
However, there would be rules. No legendaries on your team, no "perfect undefeated trainer." If you have a rare pokemon on your team, you should come up with a legitimate-sounding reason as to why. Also, we would be trainers-- humans-- so no RPing as a pokemon.
And to make it really clear, please please please don't write yourself in a relationship with a pokemon, because that gets really uncomfortable really fast.
Anyways, that's the basic idea. I'm always willing to hammer things out