Here is the Thunderbolt to HDMI solution from a company I believe to be reputable http://www.aja.com/en/articles/172/

T-TAP provides video professionals an easy setup solution via its simple, single Thunderbolt cable connectivity for both power and data. Offering the ultimate in portability, T-TAP is lightweight and smaller than a standard mobile phone. T-TAP supports everything from SD to HD to 2K and 3D with pristine 10-bit quality, even over HDMI, and all with 8-channel embedded audio. T-TAP includes AJA's renowned Mac drivers and software for integrated compatibility with major software packages from Apple, Adobe, Avid and many more.

"T-TAP delivers uncompromised video and audio quality and tackles a range of media output needs at a very low cost," said Nick Rashby, President, AJA Video Systems. "Packing a lot of power into a remarkably small form factor is what T-TAP is all about."

T-TAP Key Features:

High-speed ThunderboltTM connectivity
10-bit uncompressed 4:2:2 video and audio output
HD/SD SDI and HDMI connectivity supports simultaneous output at incredible 10-bit quality
3D support on HDMI for real-time stereoscopic review without requiring additional hardware
Full 8-channel embedded audio allows for multi-channel playback
Bus-powered via ThunderboltTM connector so no additional power supply required
AJA Mac driver and proven software compatibility
Backed by AJA's quality, reliability and 3-year international warranty

T-TAP will be available soon through AJA's network of worldwide resellers for a cost of $249.00 US. For a complete set of features and technical specifications, please visit www.aja.com.

About AJA Video Systems, Inc. Since 1993, AJA Video has been a leading manufacturer of high-quality and cost-effective digital video interface, conversion, acquisition, and desktop solutions supporting the professional broadcast and post- production markets. With headquarters in Grass Valley, California, AJA maintains an extensive sales channel of dealers and systems integrators around the world. For further information, please see our website www.aja.com.