Here is a buildable elven tower that can be upgraded to elven fire tower, elven magic tower, elven arcane tower and ice tower.
Maybe elf fan and tower defense makers will find this useful.
Credit can go to blizzard for the original (so cewl) elven tower models, and to me if you think there is enough place in your map. However, credit may NOT go to you or someone else.
If you have any suggestion, just PM me at wc3c or email me at "armel.nicolas@ens-lyon.fr".