A bunch of groups (including us) are working on open source I2C ESCs, which will be cheaper, better and easier to integrate into quadcopters than commercial ESCs. Here's one such project.
This guy is also working on "cloning a Chinese clone" of the MikroKopter quad controller. He reports:
"Everything works as planned.
Features over the ChinaFC-1.35:
* 4 layer PCB with proper ground / power plane
* Pan/Tilt/??? servo output like on OEM MK 2.x
* 3V reg for Spektrum-satellite receiver
* Switching DC/DC regulators instead of 7805
* MK-compatible molex connector for distribution board for I2C/Power/Buzzer
* $68 BOM cost"