I was thinking you could remove that brace and then replace it when the sump was installed... but now that I think about it, your stand is not wood is it? Is it that beautiful black glossy acylic?
Oceanic should really make the size trade with you. And the little bit of a price difference should pay for the shipping. Have you heard anything from them? Also plumbing the bigger sump to the side, or though a wall will work fine.
Its really just what you want to do! If you didn't want to mess with the Oceanic sump, replacing it with another sump doesn't have to be difficult or expensive. Really any ol' tank will do. In fact some people are using food safe tubs from Rubbermaid! I can come up with some pics if you like.
Our ugly 45 gallon sump is WAY overkill on our 90 reef. I never worry that it will overflow when power fails. So really, you have tons of options!
This months edition on Reefkeeping Magazine
has a nifty article on sumps. Its crAzy what some people come up with! But it just goes to show, your sump can be just a place to put a skimmer, some heaters and carbon.... or it can be a mini refugium with baffles and a mangrove farm!
Keep us posted! Gabe and I would love to lend a hand! We have tons of plumbing bits and glue! =P