On the raspberri pi blog are instructions to cutaway one side of a 3b+ box to expose the new USB-C power supply and both the micro hdmi ports. The other three sides have the same layout.
The price of the older models 3B(+) will stay $35, just as the Pi 2 B+ is still $35 excluding taxes.
The reasons are: industrial use and a diminishing economy of scale. There are less production runs for these models. (They keep only limited stock)
Info about pricing for older models is on the Raspberry Pi website.
Note that you have to expect some niggles, because not all software is already ported to the new RaspBian you need.
Also I read some - varying - rumors that the high resolution video play back is not yet up to scratch.
OTOH the new VC6 GPU seems more standard and better accessible than the olf VC4 GPU.
I also ordered a passive heat sink, since the CPU seems to run quite hot at full load.
Well, have to test all that in the weekend (hopefully)