Looks like that tank is made for a sump, so I would advise to go ahead and get the sump, then get a skimmer that is made to go into the sump. It looks like it's already drilled on the back, so if your not going to do a sump, then youll have to cap those off. But I dont think your going to find a skimmer that will fit on that lip. Probably have to cut the acrylic lip down to make a skimmer fit on there.
But personally, I would just wait and buy the sump, pump etc and set that tank up the way it was designed before cutting anything myself.
My seaclone works great now that I've modded it, but it worked okay for the price of it originally at $79.00 on sale locally.
Good luck,
EDIT: After a little more thought, it looks like top plate is thinner on the sides, then at the front or rear, so it might fit on the sides, but you'll have to measure to be sure. Other than that, you could modify the seaclones piping if you wanted to. You could basically cut the intake tube on the straight section, and either use a flexible aquarium hose with a hose clamp, and then run that over the top and connect it to the powerhead with the other piece of connector. See crude drawing:
AND DO AT YOUR OWN RISK BECUASE IF ONE OF THOSE HOSE CLAMPS COMES OFF, YOUR GOING TO PUMP OUT QUITE A BIT OF WATER FROM YOUR TANK TO YOUR FLOOR.