I've put together a really basic interrupt driven servo library that works fairly okay on ATTinyx61 series. It uses Timer1 to control up to 8 servos. Perhaps this could be added to the AVR libraries since there currently is only a library for ATTiny1634? Or even better if it could be merged to create a more universal library. This may, with minor modifications, work on similar AVR 8-bit controllers.

https://github.com/AtomicCactus/Servo_x61