David, I've been told many times I'm full of it, but I don't think it's wisdom!
The MKVIII single fan is apparently a very good solution if you know a fabricator who can do a proper shroud for you. I have one of these at home and measured the fan once before but I've slept since then and can't remember its diameter. Think it's around 17"? But twin 14" SPAL's ought to work for you if they're in a good shroud. I wouldn't mess with the cheapie $79 stuff from Jegs or Summit for your application.
I've actually been scheming to try to build a sandwich type, integrated radiator/intercooler that would have at least two, and perhaps three sections, plus a purpose built shroud and fan setup. The front section would be the intercooler for turbo applications, then the middle section would be 3/4 A/C condenser and 1/4 oil cooler and the rear section would be radiator, then finally the shroud and a couple of honking big fans. Probably a pair of 14" high performance SPAL's running at higher voltage than usual to get higher speed.
The whole thing would bolt together and be gasketed to assure no air leakage, however I'd probably incorporate some flapper seals around the edges of the shroud that would stay closed when the fans were in operation, but would "flap" open when the fans aren't needed. This would keep the fans & shroud from blocking air flow at high speeds.
Although it would bolt together with long through bolts, it could be easily broken down for maintenance. I've approached a couple of high performance radiator suppliers with the idea, but they say they don't make the types of cores required, there's no electric fans available that could pull through that thick a core, etc., etc.. As usual, I can't find anyone stateside that's willing to try to think out of the box, and I'm being my usual pigheaded self about it, and still think it's worth pursuing.
This would be the mother of all cooling setups if it worked.