I'm not sure why you want to substitute for pullovers: are they uncomfortable for you? Do you just not like them?
Pullovers are great because they are about the only at-home exercise you can do that more closely simulates pulldowns that you can do in a gym. Quite a few weight training books state that pulldowns work the width of the lats , while rows work more the thickness. I don't know how true that is, but the two moves (pulldowns or pullovers and rows) do work the muscle differently.
However, I NEVER do the pullovers the way Cathe does in PUB (holding the ends of the dumbbell). I can't safely hold more than a 15" dumbbell that way, because of small hands, and I look to safety first! I hold one end of the dumbbell in both hands.
If you have a weight machine that allows you do do pulldowns, you could use that instead of doing pullovers. Or, if you have heavy resistance bands (like Bline bands that are sold at
www.beachbody.com , of Lifeline bands (both of these are actually more like heavy rubber cords with handles), and a way to safely attach them at the top of a door (I found a very safe and effective door attachment at
www.sissel-online.com ), then you could do pulldowns that way.