FunPhotons said:
Sorry, but I didn't think I was - I was asking if you'd confirmed that the advice you offered, indicating a 600EX-RT could be used to remotely trigger a monolight, or if you were making an untested assumption (if I was going to be snotty, I'd have asked if you were talking out of your ass-umptions...

).
I have not tested what you're suggesting, so I don't know that it
won't work. So, I'm making an assumption, as well. But, I think it's pretty likely that Canon will, at some point, release a standalone RF receiver for their new RT system, to allow compatibility with older flashes (probably a hotshoe attachment, it may or may not have a cable output port, but if not a FlashZebra hotshoe pass-through adapter would solve that for less than $20).
To maximize their profit (and the goal of any publically held company is just that), they likely will not release such a receiver until after the 430-type RF flash is released and sales of both 600 and 430-replacement have slowed down a bit. In the meantime, I assume that Canon will have taken steps to ensure that a simple cable attachment to the 600EX-RT with some splitters cannot be used to radio trigger a bunch of 580's from a single slaved 600 - Canon wants you to buy a bunch of 600's, of course, or failing that, wait and buy a bunch of 430-replacements, since those solutions mean more profit for them...