I've been keeping my eyes open for a way to run ML on the current rMBP. The reason being is that I have an expensive bit of software that won't run in Mavericks. In an ideal world I'd just clone my current drive onto a new rMBP and go. Most opinion seems to say this not possible. But at the Apple Store today I was speaking to one of the geniuses who told me that it is possible. He said that it you wipe the SSD on the rMBP, then do a clean ML install to it. That will enable the rMBP to run. Then use Migration Assistant to copy all your programs over. Anyone done this?