Zalman's ZM-VE400 is an excellent product, allowing you to dual-boot most (already bootable) ISOs and IMGs from a standard notebook HDD, emulated either as USB or CD/DVD, and from an NTFS/FAT32/exFAT partition, as long as it is the first partition on the drive. I used to own one when I had my last notebook, it proved quite useful. And it can also be used in dual-mode simultaneously, as both CD/DVD on the primary partition, and a standard 2nd partition.
However, I was never able to get it to boot an ISO/IMG in UEFI mode (on a UEFI-capable PC). It also didn't work well for my (ex)-friend, who has a Toshiba notebook. His PC would only see it as a USB but not CD/DVD, whereas my previous PC could use both.
Zalman's support is also ****, their reps take forever to get back to you, are generally unknowledgable, and somewhat stuck-up. And they make you wait forever on the phone. My device tended to have a high failure rate as well, if reviews I read on it are any indication (mine didn't have a chance to go out, since it grew legs and walked away before that could happen).
Edited by Enigma83, 28 March 2015 - 06:33 PM.