This thing is possibly crap, but I'm posting it anyway just in case someone could maybe get a little bit of use out of it so my time spent designing it wouldn't be entirely wasted.

I made this for my DIY printer but then switched to the fan being angled instead of 90°, so I haven't printed or tested this in any way (and needless to say, it's not flow optimized).

I included the sketchup file so feel free to go to town modifying it :)