JP Weigle is good stuff and you don't need to use it very often - once every two years is generally sufficient. WD-40 is a bad idea in general as it would strip the grease away from your BB & headset bearings.
which is pretty close to what the JP Weigle stuff is... wax/linseed oil/carrier based rustproofing.
WD-40 ain't gonna do any good.
T-9 would be a good alternative. It works great as an anti-corrosion coating, which is what it was designed for by Boeing anyway. T-9 is pretty thin, but very effective.
Something called Fluid film works just as well. It is a lanolin based product.
I would go with the Weigle because of the name and the support of a frame builder.
fluid film though. That stuff is flat out incredible. http://www.eurekafluidfilm.com/
I've had years of experience with that stuff in the corrosive salt of Michigan. it is amazing. the nice thing about it: it cleans up with hot soapy water. Hot water doesn't really move it around much and cold water doesn't do anything. It will stay on a vertical surface and despite looking "wet" it doesn't go anywhere.
To summarize... In order of preference (although first and second are interchangeable)
i wouldn't use it for chain... too sticky. Same reason i've stopped using T-9 as a chain lube. Picks up too much dirt.
i actually use it to oil my foam air filter in the car.
Best lube for CX i've every used is the EVerLube stuff. ErikV's recipe is killer. Narry a chain problem through the season, and even now with riding in slushy 15 degree weather with salt and all that - the chain is kicking ass (no rust all happy)... that's the chain lube to use. (cheap too, ~$12-15/gallon).