There are TONNES of Jonas fan-fics on mibba.com! I write them, as well as thousands of other stories out there.. You have to sign up (if you already haven't) and then I can recommend a few stories for you.
http://member.mibba.com/127039/stories/
http://stories.mibba.com/read/176793/Nevermind-Me/
&& If you like Nick, I VERY MUCH recommend this one: http://stories.mibba.com/read/178820/Youre-differentI-like-that/