Is there a hotkey modifier for G that sets rather than moves the coordinate? Is there a modifier for the G hotkey that sets the vertex global X/Y/Z location, rather than moves it relative to the current location?  (Something like GG X 12.5 to directly set the global X coord to 12.5).

I'm using blender to render a number of simple 2d textured shapes (orthographic projection) that directly face the camera.  

I add many shapes to a single blend file so I can position them relative to each other and then render them using a script.

At present I have to position vertices by clicking on the Info panel, Transform section, X,Y,Z coordinate textboxes and manually typing. 

I find this quite slow when I have to do this 20 plus times.

I can use vertex snapping (to other objects) sometimes, but this is no use for vertex locations that are not identical (ie offset).  

This would be also useful in the UV Editor.  I would like to be able to select a vertex and simply set it's U or V in a similar way (ie to line the vertex up with the edge corners of a simple quad texture).

I've read the online documents for the Transform keyboard shortcuts and nothing like this is mentioned.
Unfortunately I think the closest you can get now (without some python custom operator stuff) is resetting to the origin (&#9095; AltG) before moving the object. So:


&#9095; AltG
GX X coordinate
GY Y coordinate
GZ Z coordinate