Would be neat to have a google map below the holdings table that showed you the branches that had the items you wanted and a count of how many items were at each branch. This would be a mashup of the marcxml, the branch data, and google maps I would think. That way you could click on a marker on the map to see that branch's info and get directions etc
It's a neat idea although Google Maps has required credit card details for several years now. Of course there is Open Street Map but they ask that you don't use their tile servers for public applications. I suppose a Koha library could run its own tile server, of course. This also probably wouldn't scale well for a large number of items.