Encrypt NAS drives?

As far as I can see, there are two options for encrypted NAS.
The first is to have an encrypted file container stored on the NAS which is mounted by the client machine.
The second is to configure a dedicated server that mounts and shares encrypted partitions.

The first option would be more secure, but I have no idea what performance impact you would have piping it all through your network.

The second option is quite a bit more convenient and I believe it would be quite a bit faster as well, assuming the servers processor is capable keeping up with your workload.
It has an advantage of lower resource usage on the client side, but is less secure in that anyone on your network could conceivably access the files anytime the server has your drives mounted.

Probably there are more options as well (which I would also be interested to hear)?
I am assuming there are corporate quality NAS systems with better encryption options on the market somewhere, but I doubt they would be really affordable  

It sounds like I should just simply use a TrueCrypt encrypted file container. (encrypt a folder to one file before copying it to the NAS).

What happens when accessing the NAS from multiple machines then? If the NAS gets a file lock them it'll be ok-whichever machine gets the lock can write to the file and the other cannot. if there is no file lock them you could end up destroying the TC volume file.

This is more of a question than an answer, but a question i would like to know the answer to

Hard to say, since each encryption method varies. True Crypt is tied to a specific system if I do recall correctly.

Best answer selected by enewmen.