Y'know, i know of a project called The Legend of Zelda Online: Ocarina of Time.
what it is, is basically several maps from The Legend of Zelda: Ocarina of Time re-made for multipayer play with the downloadable Halo Custom Edition for PC. it's basicaly Halo style Zelda, only they're changing everything so that it basically plays like a multiplayer PC version of
Oot that runs on the Halo engine for the PC.
you can find it here:
http://www.projectzeldaonline.com/
so there already IS an unofficial fan-made Zelda online game in progress of development, however it requires that you have Halo Custom Edition (which in turn requires Halo itself) on your computer.
i have Halo, and i look forward to downloading Halo CE, so when it's all finished i may very well get the Zelda Online map packs.
everything about Halo will be replaced with Zelda style elements. vehicles like Warthogs will be replaced with horses, banshees will be replaced with owls, weapons will be completely different, so that they function similarly to Zelda weapons and even look just like their
OoT counterparts, and even new weapons like Link's swords. the Spartan biped will also be replaced with a custom-made Link model that you play as your character, and will be using a 3rd person view mod, and the Halo HUD will be replaced with a Zelda style HUD. and that's among a lot of other changes as well.
just click the follow the link above and you can read all about it, watch videos, and view screenshots.
i'm not part of the project, mind you, but i am in much anticipation for it to come out.