Atm, linux-3.0 is actually linux-3.0.0, since removing the SUBLEVEL variable from the Makefile would break userspace utils, including procps/uptime (patch available), depmod etc. However, it's likely that future 3.x kernels will remove the extra unneeded variable from the Makefile (when patched userspace utils hit the distros I guess), and this will break the linux-info.eclass, and it'll need to be patched. When I have some free time, I'll try to provide a patch for testing. Thanks.
IIUC, the third digit will be claimed by stable queue releases, so the var may just change the meaning.
not sure if anything needs to be done here anymore