Ditto. I’m looking for exactly the same thing. Simpleviewer will do this (outside of WP, and maybe within), but it uses flash, so unfortunately it won’t work for visitors to your site with iPads. Simpleviewer is working on a non-flash version- not sure when it is due out.
Apple features a horizontal scroll on this site- http://www.apple.com/html5/, see gallery, but it lays the highlighted image over the thumbs. It’s a CSS/html5 solution, but I don’t like the navigation as much as simpleviewer.
I’m working with tanzaku and installed NextGen Gallery.
I have not had a problem with this plug-in with this theme so far. Error free, but not sure if it can do what you want.
