I live about 45 minutes from Baltimore and I think it would be awesome, an East Coast U.S.A sized map of Baltimore City, Maryland.
I know this isnt your intention, but when people ask for free mods it almost always sounds like this in the community's head: "OMGGG modders make mods for FREE?? Hey free labor guys, whip me up a mod of an entire city and first one to do it gets a thumbs up!" its not a huge deal, but i can still guarantee you wont get a mod even if it did work that way, this wouldnt be the right thread.
Simple: leave a direct message for a modder with your mod request. If they care, they'll try. If not, you're out of luck.
You make it mate! You can use LiDAR data to figure out a lot! (i've never made a map, but I do think LiDar would help a lot)