Do I think there is a chance of Apple making a 17" rMBP? No, at least not any time in the near future. But I certainly wish they would.
I use a 15" rMBP for work, and used a 17" MBP for work before that (and I still use a 17" at home). The 15" rMBP is great, and the 1920x1200 equivalent mode is a good enough compromise when coming from the 17". I use an external display most of the time, but the 15" in 1920x1200 mode is usable if I'm sitting at a disk with my face close to the screen, but not so much if I was laying back and my face is further from the screen and I use best-for-retina if I'm in such a position.
The 17" display of the old MBP is just glorious. A retina 17" would be absolutely fantastic, especially if I can use it in a 2560x1600 equivalent mode, since that is the resolution of the external monitor I use. This would be a great work machine for me. The 17" cMBP was already an acceptable size for the way I use it and a thinner, lighter 17" rMBP would be perfect. The portability of the 15" rMBP is nice, but unnecessary for the way I use my work laptop.
Extra points if they can fit in another drive in a 17" rMBP. I'd like a 2.5" drive bay, but that isn't going to happen -- but if you could do dual PCIe SSDs and RAID 0 them that would be insane. Or at least give it some hardware advantage over the 15", like better GPU options.