I've been running all this stuff from VMWare generally too. I just got Samsung SSD for the machine and DAMN it's a huge difference. I just decided to try the boot from USB because I have been making a sort of "OS Keyring" with about 5 flash drives with different OS that I might need for various things. Tails, LMDE, THS-OS, Win8 with Visual Studio, etc.
OE: I've seen the rEFInd stuff but I'm not 100% sure I want to do what seems like replacing the boot loader on my mac... I was able to use something last night called Mac Linux USBhttp://www.makeuseof.com/tag/how-to-boot-a-linux-live-usb-stick-on-your-mac/
I got it to at least show me a drive in the mac startup manager. It came up as EFI Disk or something like that and was the typical orange "USB" drive icon. It tried to boot but had some problem. That's the furthest I've gotten so far.
Interestingly the utility has an option to "bless" the drive which from my limited research seems to be the equivalent of marking a partition as "active" in the new OSX world. Will keep playing with it but I'm keeping rEFInd as a last resort for now.