The Jumpdrive mercury is a disk-on-key (1GB/2GB), with an e-ink capacity meter.

Lexar jumpdriveLexar jumpdrive

The nice thing is that because e-inks do not use any power when the display is constant, the display can be on even when the drive is not connected to a computer. 

The JumpDrive mercury is available through Amazon, for 9.99$ (2GB)

E Ink display info: 
0.7mm think E Ink bar graph display