I'm not sure what you mean by 'built in', but I use it under OpenSUSE. it is not part of the default install, but is easy enough to add.
Should have first have clarified the 'it' bit, too. E16 and E17 are quite different and look quite different. E17 is a 'work in progress' but most of the time, a lot more of it works than KDE 4.x (imho, ymmv, etc, etc). And it is attractive, without being heavyweight.
For e17, you have to add a slightly obscure repo like this
, and then select e17 and maybe a couple of theme packages (23Oz, 2be), if you like, and, short of a download, you are done.
I already tried ELIVE, but they won't let you install for free!!!
Yes, I heard that; really puts people off, me included.