With the release of the PS Vita, Sony now has 4 separate systems on the go at the same time, PS2, PSP, PS3, PS VITA. Has this ever been done before? Just curious.

Yes, Nintendo:

Wii
DS
DSi
DSiXL
3DS
and soon to be
Wii U
and Modified Dual Stick 3DS

That's only 3. DS, Wii and 3DS. DSi, DSIXL are both DS's.

Would remodeled systems really count though? Cause that Would mean that Sony would have all their different types of PSP (PSP, PSP1000, PSP Go)

EDIT: Actually at the beginning of this gen didn't Nintendo have the Gamecube, Wii, GBA and DS?

 I can't remember. Did they cancel production of the Gamecube before they released the Wii, or did the Gamecube and Wii co-exist for awhile?

All the DS systems play the same games. So, no, it doesn't count. 3DS counts... Those individual models don't have specific games designed specifically for those models... And, PSP and PSPgo does have games specifically for different models (Megaman Powered Up says hi.) If anything, that should count, but, even-so, it's just the same system without an eye.

You maybe could make a case for the PSP Go, but for me it's still a PSP.

Nintendo had the Gameboy Advance, the Gamecube, the Wii, and the DS all on the market and selling around 2006/7.

DSi, DS, 3DS, and Wii. Technically DSi does have specific DSi games, both downloadable and available at retail - the hardware is about three times more powerful than the DS; and there are still games coming out for all 4 platforms. Also, technically in 2006 (and perhaps into 2007), there were games coming out for GBA, DS, Wii, and Gamecube.

Thanks for clearing it up. They'll do it again sometime in 2012, DS, Wii, 3DS, Wii U.