OTOH, maybe it's just a rental: Google Wave and Nexus One haven't exactly set the world on fire. Particularly interesting are lessons learned from Nexus One. Google attempted to upend the existing business model with mobile netops and their onerous handset contracts. However, selling an unlocked phone at full price apparently wasn't that revolutionary.
With Android TV, Google may wisely go back to more of a Microsoft model. Let the hardware vendors deal with manufacturing, distribution, returns and tech support. Much like Boxee working with D-Link to build a Boxee STB, or VUDU changing emphasis from a STB to embedded systems, Google's value add is in the software.
I've been following the bits of Android development in the TV space, limited as it has been. The major hardware development has been the MIPS / Sigma Designs Android System-on-a-Chip (SoC) design. It has been incorporated into a few Android STBs (MIPS-based Android set-tops debut). SoC announcements generally aren't that exciting, but are a critical part in delivering a new STB. Unclear if the early-adopter MIPS / Sigma SoC is part of the upcoming Google I/O announcement.
My favorite Android TV announcement has been from the Swedish company People of Lava. If only because of their name. A name we can appreciate in Hawaii. They announced an embedded Android TV set. No, it does not include a lava lamp, they missed the marketing opportunity there. (World's First Android TV Comes from Sweden)