Righto, first off, I've read the other posts about chelsea grins and the like, I'm not on about one of those. I want to have my mouth widened, seamlessly. I want my mouth to look normal as possible until I open it. HOWEVER I do want it to be subtle only showing a few more teeth than normal ect. I want it thus that people would say: something was strange with that person but i can't really place what.
Is this possible?

A skilled plastic surgeon could possibly do this. I do not think that many body modification artists would be confident to do such a technically complex surgical modification. 

This may not help but, I do at one point remember seeing on the Internet somewhere a video of a girl( if we were stopping here this wouldn't be that surprising but..) she had this thing in her mouth( not surprising either), it was made of plastic(-_-) and basically to describe it was two square pieces and a spring in the middle. She pressed it together with her fingers then put it sideways in her lips and the spring released pushing the two square parts apart which pushed out the corner of her mouth, non-surgically stretching it. Am still trying to find the video. Actually it may have been on one of those clip shows from the Internet on tv. Oh well best of luck to you with this. Will post vid link if I find it