I don't see the 360, WiiU, or PS3 (or the next generation consoles) being emulated anytime soon though.
There are emulators, though they tend to completely tank your system unless your specs are godly.
Yeah, "soon" was referring to probably any time in the next year or two. After that, both the hardware might have advanced enough to make emulating them possible, though even with the original Xbox emulation is next to nothing right now - doing a quick search one night trying to play my old copy of Sudeki without digging everything out hardware-wise to play it, it looked like only Halo 2 was running at anything playable, and that was it - apparently the original Xbox games had to be emulated on a case-by-case basis, hence why the 360's backwards compatibility is so limited and hit-and-miss.
So, I guess it was from both a hardware and software point of view.