The Elsweyr and Valenwood heightmaps by Onra can be modded to your liking. The landscapes are still pretty basic, so there is room enough to make a dense jungle to hide a city in. It would be best to check before building though, as there are still some cities to be build at some lore correct locations.
EDIT: Oh, and you have instant access to all the tropical plants, trees and flowers to build with!
thx StarX for the reply, Elsweyr and Valenwood heightmaps by Onra could have work, but i don`t need that huge of a place, i`m working on heightmap and did myself a nice big island, next step is add stuff to it, got 1 temple freeware that took me forever to fix up and slap into oblivion, trying to figure out gold, yes i got gold, but not the color i need, me its that darn gold color, remember egyptr it took me weeks to get the color i wanted for my statues, yes i`m a perfectionist for certain stuff, it have to fit in and match up.
not starting another mod, fooling around to see if i can make a buildings in 3dmax, also add a tropical island, guest i got t omake myself one
as for instant access to all the tropical plants, i got 3dmax, time and got like 10 made already, might grab a few in mods , [with modders permision] but i could make 100 in a day, pretty simple stuff, got tons of plant textures, just boring to make plants[reason i was looking for a tropical island
, if i start getting more then just a few items i might start a post, but prob would just release it on tesnexus, just working on my first building and it will take me a long time, but when i got the patern for that building then i will have that patern for the full city,
i`ll post here until then, or if u reply
so any know why this site lagggs, the new site makes me lag here, its the only site that makes me lag????????