After posting my BlogMap I thought I'd go find other bloggers from around my locality (Melbourne, Australia) by using Chandu's Blog Search page and entering my location.
The results are returned as a map (der) with an “X“ marking the spot of bloggers (13 so far). I asked Chandu if a list could be returned of all the bloggers in Melbourne, and it can, using the “blogapi”. He sent me a query to get an OPML file for all bloggers within a 20km radius of Melbourne:
Great work Chandu, this is exactly what I was after!