1. Compact, Fast (7,200 RPM) biggish (80GB) HDD in an enclosure with firewire & USB 2.0 that holds my complete desktop environment that I can use to boot any reasonably modern PC system. Also with an install of virtualization software, so I can plug it into a running system and boot my environment inside.
2. PC & Mac software that will fit on a reasonably sized (128 – 256 MB) USB drive that I can use to open a secure authenticated connection to my home PC or network and gain access to my files and remote control my desktop. Ideally initiating the connection would wake or boot my system if it was asleep or shut down. It should be able to work through most firewalls.
Both of these are possible. I may actually build them.