In explaining resolution in layman terms, 720p IS related to 1080i. Nearly any monitor that can natively display 720p resolution can upconvert that signal to 1080i resolution by interlacing the 1920x1080 lines. 1080p is not broadcast, but that's not what this guy is interested in, he's talking source hardware. PS3, HD DVD and BluRay players all natively display 1080p content.
I understand completely. And yes, I realize upconversion is possible on nearly any monitor. Even DVDs can be upconverted, and usually are on HDTVs.
The original comment I was responding to blatantly stated that "1080i is 720p interlaced." 1080i can indeed be a signal created from a 720p source, but to say that 1080i is only an upconversion of 720p is falsifying. This upconversion is also not called interlacing. While a progressive source may be interlaced in conversion, the conversion in size is done by a scaler. A scaler could upconvert 720p into 1080p without having to do any interlacing.
The 'i' in 1080i refers to the fact that it is an interlaced source, not that it was "interlaced" from 720p. 1080i is a somewhat erroneous term in that it's really 1080i60, though even that is erroneous as it actually ends up being more like 1080i59.94
I only put that 1080p tidbit as an interesting fact, it wasn't supposed to relate to the topic of game consoles, just as my comment wasn't addressed at the original poster. Also, just because it hasn't been broadcast yet does not mean that 1080p is out of the HD standard—so it could be broadcast at some point in the future.