Raidon (http://www.raidon.com.tw) has released a new, hot-swappable mobile rack, the iS1010, which comes in a tray-less design accommodating both 2.5-inch HDD and 3.5-inch HDD without securing with any screws.
 
The iS1010 is only the size of a standard CD-ROM and fits in any 5.25-inch bay from any computer casings. Even without the trays, the well-protected structure design of iS1010 ensures a well connection to the installed HDD and without any intervals possibly causing damage from vibration, according to the folks at Raidon.

Other than that, the aluminum casing with cooling fan provides excellent heat dissipation keeping HDD in a well functioning temperature during operation, they add. Contact Raidon for pricing.