Yes, Dean Camera made an AVRISP MKII clone several years back. He went open with his design, and you are free to build your own USB clone from scratch: http://www.fourwalledcubicle.com/AVRISP.php
Originally Posted by Dr Vel
Personally, I wouldn't bother making a clone since these devices can be found cheaply on ebay.
Just make sure to get an "AVRISP MKII" or other clone since you want Atmel support. Some, like the USBASP clone are really cheap (less than $5), but are not supported by AVR Studio. These cheaper clones rely on buggy proprietary software that some times come with driver issues.
Also, if you're new to the atmegas, you can build your self an Arduino board (http://arduino.cc/en/Main/ArduinoBoardUno). The beauty of this second option is that you can use the Arduinos as your main development board in addition to using them as an ISP programmer as an option ( not both). Scroll down for the Eagle files in addition to the schematic.
The Arduino boards can be transformed into an ISP programmer only after programming them with the necessary software.
Don't be shocked if you go the Arduino route. I had some experience using the Atmel processors and their free toolchain before checking out the Arduino. After getting their hardware, I think I felt insulted by how easy everything worked. Most pic guys never go back once they have had sometime with the platform.
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