UCS type deal in MOI?

 From:  Crusoe the Painter (CRUSOE)
What if you want to draw or construct on a curved surface though? Like I draw some curves, project them onto the surface, and then use them to 'cut' detail into the surface. This kind of feature would be awesome for mechanical modeling for tanks/ships/etc.

A construction plane that can easily be built 'tangent' to a surface would be awesome, it's Z axis would of course be the surface normal.

It would be cool if we could 'tack' a plane to the surface, and then recall it as suggested, like a bookmark.

But being able to 'draw' on any flat surface would be a killer shortcut too.