General :: USB To USB CD ROM Emulator?

I'm wondering if anyone knows of a CDROM emulator that runs on Linux. I want to emulate this configuration:

[CDROM DRIVE]----USB CABLE----[COMPUTER UNDER TEST]

Where [COMPUTER UNDER TEST] is a computer that boots from a physical CD inserted into the [CDROM DRIVE]. Only instead of the [CDROM DRIVE] I want the following configuration:

[CD IMAGE BUILD MACHINE]-----USB CABLE-----[COMPUTER UNDER TEST].

I want to build an ISO image on the [CD IMAGE BUILD MACHINE] and have some sort of USB CDROM emulator running on it to serve up the ISO image to the [COMPUTER UNDER TEST] as though it was talking to the [CDROM DRIVE]. Does this exist? If it does, I can't find it. I want to do this so I can test out bootable CDs without burning a lot of coasters.