I have hit on a whole bunch of similar products now. These are what I was after. It seems you just need to know where to look and what to search for.
Here's a reasonable wrap-up of what's available:
http://www.bhphotovideo.com/c/buy/St...9/N/4287966885
I'm unsure what I'll do at this stage. I am considering how worthwhile it is gettting either a 160GB "Hyperdrive COLORSPACE UDMA" or a "MermoryKick SI", both of which are available from some online Australian retailers also. Both are quite impressive, compact, useful devices for what I want. Both are reasonably expensive.
Roger.