So, I admit I use ImgBurn in a non standard way, and it (apparently) works fine, just FYI, so this isn't a bug report or anything.
I have 3 DVD burners in my computer, and theres no problem keeping them all busy at once. I haven't' noticed any burn rate degradation, even when burning 3 images from the same hard drive. (as an aside, I have scads of ram, not that ImgBurn seems to take advantage of the fact that I have 12.5 gigs of memory available.) Also haven't observed any difficulties with running multiple instances of ImgBurn in parallel. (other than occasionally confusing myself while trying to manually label all that =0.) Though that was before I knew how to use the write queue's properly.
Since ImgBurn appears to work fine running multiple instances in parallel....out of curiosity. As developers, would you expect problems to arise from this? I've been doing it quite awhile , but stumbled over a post where someone was asking if it were a good idea, and someone else indicated it would not. If ImgBurn runs in parallel fine, I see no real reason to ever integrate the ability to drive multiple burners at once, though it would be kind of neat if you could set the ability to only eject one tray at a time, and indicate on the screen the past and future image for the open tray.)
Probably not worth writing any code to the multiple-burner folks, since its kind of a rare situation. Arises when burning large series of DVDs, primarily.