Hi Mark, yeah the command Stargazer shows above is the closest thing to that.

re:
> Maybe hold down a key (without a tool selected), then click and drag to draw a guideline.

The thing that's tricky about this is that when you have no tool selected you're in selection mode and things like "built in" modifier keys (like just Ctrl click without any other keystroke) are focused on selection related things then rather than drawing type things.

- Michael