Documentation pretty much says that you only need MAC when you are submitting your app to the appstore, no word of MAC on development/deployment stage, only distribution.

I already asked to Unity and Shva 3D forums :
And yes tools to make the game can run on Windows , but
for makeing the final build and distributting it to store
you need a MAC for that last phase !

For Android , i don't know ifd a Mac is really necessary ?

Just do It !!

http://independentcreator.over-blog.com/pages/3D_Models-7792999.html