I don't think there is one, what do you think the integration sholud look like? I've done a small script for maya that send the polygon uv position from maya to photoshop selection.Maya Selection to Photoshop Paths - buliarca's scripts
But that doesn't count as integration. I think other scripts can also be done.....
Being able to easily export Photoshop documents into a 3D application and easily import 3D documents into Photoshop.
So you just want a button that automatically imports or exports the 3d layer. Take a look atyhis script maybe it is what you are looking for:http://www.creativecrash.com/script/gop-maya-to-photoshop-script/feature_requests/1736#tab s