> the focus is on Tegra, in stores since long time
To be more precise, the focus is on the ARMv7-A/Cortex-A based Tegra 2, which hadn't been in stores before September 2010 (the Toshiba AC100 being the first device using it AFAIK). The older, much weaker Tegra processors are based on ARMv6/ARM11.
How would all that (future Tegra chips, "Denver", mystery x86 compatible chip) go together? The following article may have a speculative answer:
"How is an ARM core related to x86? That is easy, Nvidia is going to use Transmeta-esque code morphing firmware to make the CPU run x86 code. [...] The take home message of this whole story is that Nvidia is building an x86 based on the next generation ARM core." http://www.semiaccurate.com/2010/08/17/details-emerge-about-nvidias-x86-cpu/
Could that actually be what "Denver" is about, having an ARM ISA based chip that is able to morph x86 code into ARM code for 3rd party application compatibility?