Thanks to Andrei, daily snapshots of sr_3.0, kamailio_3.0 and sr master branches can be downloaded from:
http://sip-router.org/tarballs/sr/
Note that new tarballs are generated only if there are changes for the corresponding branch (so if you don’t see a tarball with today’s date it means there was no change from the previous one).
The tarballs are generated via make tar, which makes sure the correct repository version will be included in the compiled binary (make tar generates first autover.h before creating the archive).