Hello, this is my first entry on this forum.
I was searching for help on this impossible task ("how to program an ATtiny85 with Arduino Mega). Well, after a long week here is what I´ve done to have success:
- Install Arduino IDE 1.6.4 (on Windows 7 desktop PC)
- Install driver for Arduino Mega (this is done by Windows automatically)
- Install ATtiny support from Boards Manager, (version 1.0.1)
- Open ArduinoISP scketch and upload to Arduino Mega
- Open Blink and select the following in my case:
Board: ATtiny
Processor: ATtiny85
Clock: 1MHz internal
Port: COM4 (Arduino Mega)
Programmer: Arduino as ISP - Hit on File-> Upload Using Programmer
And magically all works!!
I´ve test others IDE version but I´ve no success. The only one that works for my was 1.6.4 
This is the Pin connection that I use, plus the 10uf Capacitor connected on Rest pin (Arduino Mega) to GND
Pin connections to Arduino Mega:
ATtiny Pin 1: Pin 53 ATtiny Pin 8: VCC
ATtiny Pin 2: S/C ATtiny Pin 7: Pin 52
ATtiny Pin 3: S/C ATtiny Pin 6: Pin 50
ATtiny Pin 4: GND ATtiny Pin 5: Pin 51
Remember to use the capacitor after upload the ArduinoISP sketch.
Regards from Argentina!!!