Online Community of Zenith Builders and Flyers
I don't have the files (building a Cruzer), but you might contact Zenith directly. I cannot speak for them, but, based on my experience with other kit manufacturers, you will probably not be able to obtain a full set. Think about it - if you had the files and were hacked, or you gave away the files to a really trusted friend, Zenith just lost out on revenue from multiple sets of plans. And probably any parts sales revenue as well.
Again, I can't speak for Zenith, but they're pretty decent folks. If you wanted the file for one unique part and not the whole set, I can see where they might think about it for a few minutes. Best bet is to call Zenith. I have yet to meet an unscrupulous Zenith builder, so if someone developed their own files, I doubt they'd give or sell them to you for the reasons above. Very admirable goal you cite, to make your own parts, but we have to protect Zenith as well!
Again, I'm just caveating, but I vaguely recall one mfr telling a builder (think it was Sonex) that if that builder wanted to create the CNC files to make their own parts, go for it. They just admonished that that builder would be expected to NOT sell or give away those files to other builders. Bottom line is that you have to fabricate the parts - doesn't mean you have to use a hacksaw and channel locks to do it!