New SLK Rows

Is there any way to actually add new units/abilities/w-ever with only SLK manipulation? I mean... there's a few free slots such as Flamestrike (Creep) and Flamestrike (Creep Improved) which can simply have their base ability altered and rebuilt, but well... can I add new rows? and new units?

Also, if I create new units, is there ANY way to change how this is built? through data file manipulation, or am I looking at PE exploration?

cheers,


'tek