Wikimapia has some buildings geolacated. Not a solution, but it may help in some cases.
A problem we have encountered is that local administrations in Spain are using coordinates in UTM ED50 format. We use a spreadsheet to convert them into GPS format, but it is not precise enough for landmarks. Geohack does not have UTM ED50 format.
> Subject: Re: [Wiki Loves Monuments] Coordinates tools & pan-European sponsorship
>
> On Mon, Mar 28, 2011 at 09:32:58AM +0200, Edo de Roo wrote:
> >
http://toolserver.org/~multichill/coordinates.php?type=empty®ion=empty&template=Location
> >
> > This is the coordinates tool that is used on the Dutch wiki.
> > It generates the code for the wiki-template, by picking a place on the map.
> >
> > I hope this helps us all out..
>
> I am currently working on improving this one. My current version will do
> any changes you do directly to the generated template, so you don't need
> to click the coordinate again, and with help of Dispenser, the maintainer
> of the geohack tools, it can select the region automatically. I will move
> this version shortly to multichill's version.
>
> If we should support other templates for other wiki's, I can look into that
> as well. For the auto-edit tools to work, some javascript should be
> installed on that wiki, but then I can add it to the list.
>
> I am thinking of moving this to a project account on the toolserver, so
> if others are willing to help with this, let me know.
>
> Regards,
>
> Andre
> >
> > Edo