We thought the whole pen convergence trend had subsided after seeing the most recent combo devices with built-in camcorders and DVRs. But video is apparently only the beginning for the versatile writing instrument, which also has designs on the storage market.
There have been many USB memory pens, as Chip Chick has noted, but now things have gotten downright silly with an SD card reader. The "3 in 1 Cocos Card Reader" also has a USB drive and actually writes, hence the three functions, with storage of up to 512MB.
But unlike the earlier surveillance-oriented pens, we wouldn't recommend this one for covert activities. A pen with a rectangle sticking out of it isn't exactly an everyday sight.