My Idea for an ION PC is one camouflaged as a book. Nothing too fancy, I was thinking a nice retro look, but you could make it as tacky as Twilight *shudder*.
Standard connections out the back, power light as an option in the front. After all, a book with a power light is a bit conspicuous . Slot loading DVD/CD drive in the spine.
Another option would be to make it look like 2 books put together, that way, the slot for the CD drive can be disguised even further.
Since the ION is a low power platform, heat dissipation should not be a problem. External power brick over an internal power supply is preferred. Throw in a wireless card, and you'd only really need 3-4 things plugged in at once (kbd, mouse, power, speakers).