Creating an empty stream?

I would like to create a stream and copy a bank to it, without actually having any file on the hard drive or internet. How do I do this? If I just use New TStream, I get errors saying the stream is not writable.

Assuming this is possible, would reading from a stream be any slower than reading from a bank?

Can't use use CreateBankStream or maybe CreateRamStream?

CreateBankStream is perfect.