According to this comment, it does not make sense to build p11-kit statically. But looking at systemd expression, (libudev is an alias of systemd), the dependency is optional (systemd.override { withHomed = false; }). You can also try to use systemdMinimal, which disables most of the dependencies but still contains libudev. Edit: Actually, withHomed is disabled by default so p11-kit is likely pulled in by some dependency and it might be necessary to fix that first.
Generally, pkgsStatic, like anything, are maintained on a best-effort basis. If the build fails, the solution is to fix it in Nixpkgs and you can help with that.