Agreed Dale, get those bottom bulkheads on a closed loop. Ideal situation. If its quiet you want then, a Mak 4 is an excellent pump.
I have never seen an inline skimmer. Would it not have to be under pressure then?
Again of quiet is a concern and you dont want to go with a Euroreef, then again I suggest, having Jayson or Titus build you a duel injection beckett, to what ever height you wish. That way you dont need a large single noisy pump. Just a pair of Mag 24,s in the sump or better yet a pair of Mak4 pumps in the stand. Although you can hear the fan, its the most quiet fan cooled pump I have ever heard. I cant hear my friends with his doors closed.
The thing to make sure of, is how well long term a beckett will run in the sump. Some say you cant adjust then correct that way. As mentioned, mine worked just hunky, but it was not a long term test.
To sit it inside the cabinet, but not in the sump, it needs to be high enough to pipe over the side and down, then run along the sumps water surface.
Thats pretty hard to do without a high cabinet, so most have a cabinet attached to the side, thats higher with the skimmer in there. Some just sit it beside the tank.
However, like I said, mine seemed to be fine in the sump.
I can check, but a friend "Andy", on the Ontario board, runs his 32in. duel injection beckett in his sump, I think.