I used a 16" GM fan from an 89 park avenue for 8 years or so. Its the larger version of the fan Dave Barton's page is about, and I think its the same fan 240Shildy posted. I really liked it overall, very reliable and moved a ton of air. It was nearly exactly the same size as the stock radiator and easy to mount with a couple angles on the bottom and a couple bolts on top.
I found a Volvo 940/960 fan in the junkyard a few years ago and just recently installed it instead. I'm much happier with it. It is quieter, looks more factory (those big braces on the GM fan were pretty ugly), and I think it pulls more air. I wouldn't go back now that I've tired it. I used the relay and wiring from the 940/960, though I wired low speed to my old saab lower-radiator hose switch, and the high-speed to the switch in the radiator as additional overheating protection.
I don't remember your radiator, how much different is it than the Volvo one? If a 940/960 fan fits then I'd got that route for simplicity. As I recall you have tons of room between the engine and the radiator, so you should be able to fit just about anything if you want to fabricate a shroud or graft two shrouds together. Me I'm lazy, I'd measure your radiator and hit the junkyard looking for fans with a shroud the same dimension.