Using a 32GB or 64GB USB 3.0 Thumb Drive (I would look at one rated for Windows 2 Go) you should be able to run the VMs...Hmm ok, need to check that, I would be looking at using virtual box and one of the appliances from the oracle site. I can cut it down and remove the developer tools and just leave me with 11g database only. Any reason why you couldn't stick the vm on a USB key or other external storage?
I suppose in a way, I would be interested to know if anyone has found out things that they cannot do on the pro, that they thought they should be able to, if that thread already exists, please post the link.