A new version of RPi has been anounced on February 2015 at the same price as RPi B+!
This is a Quad-Core 900MHZ ARM A7 processor and 1GB of RAM memory.
Broadcom were willing to step up with a new SoC, BCM2836 with all the features of BCM2835, but replaces the single 700MHz ARM11 with a 900MHz quad-core ARM Cortex-A7 complex: everything else remains the same, so there is no painful transition or reduction in stability.
Raspberry PI version 2 (BCM2836)