Hmmm, I never thought this would ever be necessary, but guess that just proves the breadth and scope of Inkscape's usage, lol.

I take it you mean transferring the grid between preexisting SVG files, no? [cause of course you can preset a good grid in the Preferences screen]. I also take it you don't mean for a scripted solution, cause I reckon a good python script could give you anything... but alas, I know it not [hopefully "yet"]. ^^'
Well, it really doesn't seam like you can save your grid settings into some kind of grid file, and then load that file into another document to get your favorite grid up and running. However, how about this?
Open the file with your faved Grid
CTRL+A and delete everything.
Save As somethingelse.svg
Import your other SVG into this document
Ungroup, and pray the positioning and gradients don't get messed up much. 
With the right key strokes, it could probably get done very quickly. ^^
Granted you'd have to run a cost-ben to see if it's less of a pain to do than simply rekeying your Grid settings, lol.
