The Rebug team, know from the ps3 scene, officially unveiled their all-in-one (Flasher, RGH, JTAG) Xbox360 chip on xaio360.com:
[QUOTE]
Features:
• Opensource Firmware
• JTAG Programming of onboard Xilinx via USB (No external programmer needed)
• SPI Progamming of Xbox360 NAND via USB (No external programmer needed)
• Fast swap between SPI and JTAG modes with a press of a button
• External Oscillator (Wiring to HANA is no longer required)
• Firmware upgradable for future XAIO 360 updates (No external programmer needed)
• 100% Compatible with NAND Pro v2.x (3.0 is NOT supported!)
• Compatible with all Xbox360 models (Except Xenon and Corona boards)
• Booting of unsigned code on Xbox360
• Compatible with all Xbox360 kernel versions
• Glitching of all compatible Xbox360 models is usually within 3-25sec
• Easy 7 wire SPI installation for both PHAT and SLIM
• Easy 5 wire RGH installation for PHAT, 6 wires for SLIM
• Works as 6 wire JTAG-Interface using UrJTAG software (4 signals + power (TDI, TMS, TCK, TDO, VCC, GND)
*Required patched version of UrJTAG will be downloadable from our website.
• Compact size of 47mm x 32mm (1.84″ x 1.28″)

http://xaio360.com/