Honestly, i know a lot of people who run cv's on the rear shaft, and non-cv on the front.
That is my setup and i have no vibrations at all.

If i were you i would go to pick and pull and see if you can't find an ifs front cv.  Keep in mind the bolt patterns are different between a 4cyl cv and a v6 cv.
As well as the bolt patterns are different between either cv and the non cv pattern.  So it would be best to get the same one you already have, unless you have multiple drilled flanges.

You could swap the cv off the front and onto the rear, but then you are going to have to pay to have a shop rework two shafts instead of just the broken one.

You can give my work a call and talk to Jesse.  I am not sure what our availability on cv's are but i believe we have some we could use.
If you wanted us to build your rear shaft, we could put a different cv on it/clearance it/etc.  Whatever you decide you want.

http://www.highangledriveline.com/