Back on the heels of CyanogenMod 10.1 Nightly (stable version) for HTC One, the CynogenMod team has launched a single build of CynogenMod 10.1 Nightly for Sprint and Verizon users in the United States. The other service provider locked S IV versions are already available on the CyanogenMod website.
So, if you are staying in United States and are covered by either of the two service providers, you can download the Sprint (jfltespr) and Verizon (jfltevzw) builds at CyanogenMod's download page now.
Do remember this is the only flashable build available right now hence you may proceed with due caution or it would be rather wise to wait for release of a stable build from CyanogenMod. The news is that the stable build is also reaching final stages of development at the CyanogenMod labs. You are also requested to visit this Gapps page for further information regarding the Google Apps.
If you still want to customise your SIV the build can be downloaded as under :