A tablet with a stylus (eg: ThinkPad Tablet) would work well for that. Just grab it, fire up your drawing app (eg: LectureNotes) and start drawing. You get ea

A tablet with a stylus (eg: ThinkPad Tablet) would work well for that. Just grab it, fire up your drawing app (eg: LectureNotes) and start drawing. You get easy colour selections, box and oval drawing, and full page duplication or element copy/paste. If you don't want a full tablet just for wireframing, maybe one of those stylus peripherals (eg: Bamboo tablet) would work well. I'm surprised that you didn't mention element linking though. I would add to your list some feature that allows me to put basic actions onto an element - like a click action opening a new wireframe page. It would be great to see one of your beautiful wireframes using only those features. Sounds like a great idea for a competition. Most appealing wireframe using the fewest features wins.