Sorry if this was confusing:
src.rpm can be downloaded from the SUSE FTP server. In case of 10.0, you may need to download the DVD-SRC-GM ISO, since I don't know if the FTP installable version already exists.
You can't install src.rpm with YaST, but with rpm -i *.src.rpm. It will be copied to /usr/src/packages/. In the subfolder SOURCES you should find all patches and the kernel source. It's a bit tricky to extract single files from the rpm, but possible. You can use rpm2cpio and cpio:
http://www.rpm.org/max-rpm/s1-rpm-mi...-rpm2cpio.html
EDIT Forgot your last question:
I am not sure if you can apply all those patches to the new vanilla kernel. Some may have already been merged with the new kernel anyway (SUSE is quite active in kernel development). This is tricky!