Jakub has designed and built a USB breakout board with current monitor, an open hardware tool – USBuddy:
Do you sometimes develop with USB? I do. So I need to access data lines, bus voltage and I’d like to easily monitor the current too. I made myself a small companion (43.5 mm × 22.5 mm, 9.5 g) to do that. Just a simple breakout board with one connector in and one out. And a little extra to make things easier. I call it USBuddy.
Project info at Kaktus Circuits blog. It’s also up on Tindie.