Using an Arduino Uno to program AT32UC3B
The AT32UCxxx series microcontrollers do not have simple SPI In-System Programming like the smaller 8bit Atmel microcontrollers do. They require ICE-JTAG to be programmed. You can make a AVR Jtag Ice clone. Not sure how compatible that would be with any given Arduino or the Arduino Bootloader though.

But the other way of programming the AT32UCxxx series is... The built in USB bootloader it ships with.. No specialized hardware programmer needed. All you need is a usb cable (or cable + jack) and two series resistors, on top of the all ready required power supply and passives.

This site has the instructions to build a working bare-bones AT32UC3B board from scratch.