Apple - Early 2013 Macbook Pro with 4K
Yes, it is possible to drive a 4k Display with an early 2013 and even 2012 Retina Macbook.
1. Download SwitchResX
here
2. Create a new custom profile for your monitor
Simplified Settings: CVT-RB
Active: 3840x2160
Scan Rate vertical: 30
Hit ok and press cmd-S to save.
3. Reboot and select custom profile
Based on this thread
I have early 2013 15" retina mbp and I can drive seiki 39 4K TV via HDMI (using supplied cable) just fine.