Howdy kcart67,
Well that is an "oxymoron" for you.... a thin body acoustic guitar LOL. Generally you would expect anything acoustic to require a fairly large body to get any volume out of the thing, but I personally play a shallow body AE Ovation Celebrity and although it could be a bit louder "un-plugged" is not at all bad.
As Roger said, the Gibson/Epiphone arch-top guitars have very thin necks, and sound sweet with fast action overall. But you will find more variety of thinner neck profiles in an electric line, as opposed to acoustic. Something to do with the guage of strings and tension to achieve pitch. Played a new Ibenez today and a Breedlove, and the necks of those are very similar to the Ovation you already own (feels that way to me anyway, same thickness and radius, but the both of them had flatter fretboards than what I'm used to).
Best advice is to play everything you can get your fingers wrapped around and you will find something that just "fits".
Good Hunting and Take Care;
Doug
"what is this quintessence of dust?" - Shakespeare