I have one of the Injen short systems on my ST, its an older model but it fits just fine.
As for making your own I have an idea that you may be interested in. I dont know if anyone else has tried this but it does work and its a REALLY inexpensive way to make your own CAI. I went to autozone and found the longest piece of radiator hose they sold with the closest diameter to match my throttle body. Then got a couple of those screw clamps and a filter that would fit the hose. You will have to cut a hole in the hose for the IA sensor but the cool thing is you can put it anywhere on the hose you want
and the hose I found had some pre-fabricated bends in it so it looked like it was installed from the factory, lol. I'll try and get a picture of it for everyone to see.