I just tried to use bumblebee/bbswitch on a Lenovo T410 with openSUSE Tumbleweed x64.
Switching is only possible when bbswitch is loaded with the option skip_optimus_dsm=1.
In the case of openSUSE 12.3 the file to edit is /etc/modprobe.d/bbswitch.conf . To load the module on startup, bbswitch has to be added to INITRD_MODULES="bbswitch" in /etc/sysconfig/kernel. After that, its neccessary to update initrd by running the command mkinitrd in the terminal.
It took me a long time to figure this things out so it would be great if two things could be changed in the README:
1) Adding the T410 to the list of computers which require skip_optimus_dsm=1
2) Adding the mentioned way to get bbswitch loaded on startup and working for at least openSUSE. (I am not sure if this way is openSUSE specific, it maybe works for all distros which use systemd now)
You are free to update the README with those details and send a pull request.
README: mention kmod, workaround for T410 (Fixes GH-58)