anyone generating location-specific tinydns values?

Hi there

We have a world-wide distribution of VPN servers that I'd like to use
tinydns to provide access to the "closest" one WRT the client (really
the client's DNS server  - close enough). ie "vpn.our.domain" would
return a single IP that changes based on the Internet location of the
client. The hard part is actually associating random Internet addresses
with location of course.

Has anyone actually done this? (or approximated it). I can see how to
figure this out myself by using existing IP data against geoiplookup or
the likes, but was wondering if anyone has turned this into a
self-learning tool that can be used to keep one's own tinydns database
current?

-- 
Cheers

Jason Haar
Information Security Manager, Trimble Navigation Ltd.
Phone: +64 3 9635 377 Fax: +64 3 9635 417
PGP Fingerprint: 7A2E 0407 C9A6 CAF6 2B9F 8422 C063 5EBB FE1D 66D1