How/where do you get more accurate data than MaxMind does? And under what license do you have access to this data, and under what license would you be able to offer it to others? If all the legal stuff looks right, and the data is indeed more accurate, then of course there's going to be interest in it. I think it would take a while for word to spread and links to propagate, but eventually you'd see quite a bit of sustained traffic on that project. IP-to-location data is a very common need.
My only experience with MaxMind was the trouble we had when we got a new IPv4 assignment from ARIN. I filled out the form on their website the first week, our address was in the WhoIS records for our IPs, and our BGP announcements made our location obvious, yet they had our IP's (obviously from ARIN) showing up as originating from South Africa for months.
Seems like anyone who can look at BGP tables and whois information can get more current and accurate data than MaxMind.
Probably a lot of sources, depends how well connected you are.
The biggest one is just routing information and rDNS hosts which give away a lot of the information required anyway. If you were really thrifty you would make agreements with services (or use services you run yourself) that have users supply their location information and use that to construct a more granular database. I suspect this already happens to a degree, some of the fake information I give out has ended up in at least one IP address database.
I strongly considered doing this at one point but lacked the connections to pull it off properly (not enough sources of data I could get without approaching random people, basically). A secondary concept would just be to crowd source it and have the information freely available, but I was never sure how to deal with people poisoning the database or just honestly supplying conflicting information.
