It would be really nice if one could add geographical coordinates to a band and the search would support this too. By "geographical location" I don't mean the exact location of a house of some one-man-band, which would be a serious invasion of privacy and therefore this would have to be moderated. Adding a general location of the town where the band is currently located would be sufficient.

I had this idea when I tried to check out more bands in my local scene I did not know about after finding out that the godly Atlantean Kodex came from a neighbour village of mine and it was a pain in the ass to find every band that was within one hundred kilometers of my place of residence. If I just could have entered my geographical location and a search radius this would have been much easier!
So in a way this would support local scenes GLOBALLY (if that makes any sense )

Perhaps I'm missing your idea, but isn't this what the "Location" field is for on the band page? The city/state/territory inside of a band's country of origin where they are, well, located?

I think he wants to be able to enter a location and then have the website automatically generate bands from locations within a certain radius. Which sounds a bit far-fetched, honestly; seems like it'd be easier to just know what towns and cities are near you, I'd say.

Well, I came to a certain result by entering "Bavaria" in the location search, but MANY bands came up with this query and even if Bavaria is only a third of the size of Michigan for example, many bands turned up from places I don't exactly consider "local" (would you call 200 miles away "local"?).

The problem here is that an "area" can vary in size, but if you have a more specific location (like a town or a district of a town) and coordinates assigned to it, the search would be far easier in any case.

On the other hand there are bands coming from my particular area (I considered everything within a 100 miles radius) from places which I never ever heard anything about in my life and I never would have gotten the idea to search for bands there. So in summary my problem arises from variations in area size combined with what one considers local and my suggestion would address both issues.

Well except creating a mapping software I don't know what could be done...Most band have listed both Region/Province as well as Town/City. In some cases, one could ponder if additional locales could be used (something in between region and town) but this would really be a strain on the location field. I guess the best is still to be on the look-out for a region and then look for specific location. I realize it might be hard for a German to look for specific band when you have so many but by being more specific (like looking for all the active Thrash Metal bands from bavaria) can lead you to more manageable results.