An option for drive letters is built in.
Drive labels, I think would require a script add-in. @tbone's Tab-Labelizer is probably of interest:
I'm not sure if it can use the drive labels, but it lets you configure it to replace, say, "C:" with "Sys:" in the tab names, and similar. Doing it that way may make more sense anyway, since then if you plug in a USB stick with a really long drive label it won't make your tabs really wide.