I tried to get RAID going in Linear and Raid 0 mode. (See my other bug report on the SPARC architecture RAID problems (Bug #2807)). I was not able to get the RAID modules to correctly load until I moved the running of the /etc/rc.d/rc.modules script to before the raid is started. See the initscripts.diff file at the listed URL site.
fixed in initscripts-4.18, available in today's rawhide.