It seems that android 4.x - and every fork - has a very nice feature: Multi-user external storage. It is awesome! Every app can use a namespace, a mount point that cant share with any other app. It is very useful cause if your kernel mount a storage (network/local) nobody can access it !
More info here
That said, on android you cant use a nfs/cifs mount point. You can mount it as root - but you cant use it. Useful, right ?
And thats why i shall pass the opportunity to buy an android tablet. I prefer to wait for a proper OS - one that i can use.
Extra points: in nexus7 tablet, you cant insmod modules, there is no support for cifs but nfs is working. You cant use the nfs mount point, but it doesnt matter.