I also heard that rumour about the ports, but I'm not sure I'm entirely convinced with them releasing this new iMac with only USB-C ports. If their desktop Mac doesn't have ports, why would their laptop?
Furthering the idea of putting things into an external unit to save space on the desk, what if they also put the computing hardware into something like a power brick? Sounds crazy, I know, but the display could be very thin that way and there would be no need for thick chins or tons of dongles on the table.