haven't seen any of those... i've seen laptop mini (2.5") to standard converts aka slimline laptop IDE converter from
http://www.mini-itx.com/
btw
I/O Magic has a nice slimline 2.5" enclosure for USB 2.0 at around $50.00... I believe CompUSA sells them.
Designed to support the latest and fastest ATA133 (IDE) hard drives, this external 2.5” ATA hard drive conversion kit provides the USB 2.0 interface to connect to both Mac and PC. The data stored on the hard drive is fully accessible with either OS, and do not require separate partition. With a maximum transfer rate of 480Mb/s on USB 2.0 interface, you are guaranteed superior performance with any system.