Anyone ever build one? I have for my Buick with some PVC elbows and a coupler and hope I can do the same for the truck...
based on what you can find here, you can slap a 4" filter (K&N, etc., anything at your local parts store) right on the MAF where the airbox used to be. This is probably the easiest way to build an open element short ram intake. Pros: super easy, cheap, no water danger, sounds good at WOT, better throttle response. Cons: potentially sucks in warm air, so by itself isn't going to help your peak HP numbers or anything, if you get a filter that needs oil, it could kill your MAF, get a dryflow
A step further might be an ebay intake for around $100 that puts a silicon elbow on the throttle body and has a large diameter straight tube with MAF adapter. These are still usually SRI style, not CAI style into the fender, but they are a straight smooth, large diameter tube and replace the weird stock plastic baffling under the hood. Pros: better than a filter on the MAF, still cheap. Cons: warm air problem again, and if you go ebay, make sure the filter is legit, or it can mess you up.
Final and WORST option: take your wallet, shove it up nethers, crap out a bunch of money, and buy a name brand "intake" and have a "professional" install it. You can replicate/improve-upon pretty much any intake design for under $100 if you work smart.
IMHO the best solution is some sort of ebay/homebrew combo, perhaps ebay tubing with a good filter in the engine bay with some sort of heatsheild (I've heard mini-kegs work great . . .). I would never recommend paying the ridiculous ticket price for the major brand intake systems. A pipe is a pipe is a pipe I say, do it yourself!