I'm writing this post on a Model B Plus Pi :-)
And the good news is that there's no issue with the new CPU position on the B+. MoPi's connection terminals actually sit on C1 (a large capacitor near the CPU), and not on the CPU itself. You can see this here:
So we're good to go — initial indications are that the B+ is an even better platform for mobile power (and MoPi) than the Model B...
PS if you fire up a B+ and discover that your USB keyboard doesn't work, note that you need the most recent operating systems. One easy way to get one is to download a new copy of NOOBS and unzip it onto a micro-SD card.