sometimes local shops can make it for you like sin city in las vegas.i know this guy with a 97 ex coupe and he got custom piping and made the filter come from under the engine bay.it pops out so much you can take it.
as a warning to you....do NOT do this. I used to own a probe gt and made a beautifully crafted one out of HomeDepot parts....worked great for a while until the PVC started melting in which the gaseous fumes mixed with my air which casued my car to run horrible and LOSE power. Metal pipe you say? impossible unless you have a muffler shop mandrel bend your piping. anything else will give your air too many obstacles to get around....its just not worth it...sace the money and get the real thing man....trust me Ive been all the way down that road and back!
i know this is old, but im a n00b so im just searching through the archives. but there was a site i saw a while ago about making your own cai and the guy used 180 mandrel bent exhaust pipe and ceramic coated it. he got the pipe from jcwhitney: http://www.jcwhitney.com/product.jhtml?CATID=14721&BQ=jcw2
hum lets see $200 dollars for a CAI AEM or $50 for a custom made.... hum lets see mo money for mo stuff or no money no stuff.... do the math. It will work the same as the CAI AEM i tested the pipe and it works better than aem. and thats tempeture wise. its not called customizing for no reason. im trying to be a lil original.
Here's just a thought.... Instead of making a CAI why not make a custom sealed, insulated air box for your SRI? In theory, it should work the same way as a CAI since it'll be pulling air from under the car just like a CAI would, only the filter would be mounted higher, thus protecting it better from the elements.