With the recent migration to Fedora 8, on my desktop I decided to put the root device onto a manually created striped lvm during Fedora's install with the default stripe size across the group of 2 partitions--one on each disk.
Today, I ran hdparm -tT on the striped volume, but was discouraged by the Timing buffered disk reads--they maxed out about 60MB/sec -- pretty much the same as a normal partition without any raid or lvm striping. I backed up the install, removed the lvms and stuck a Raid0 back on. After restoring the backup, I'm back to some nice speed reads:
Timing cached reads: 1222 MB in 2.00 seconds = 611.27 MB/sec
Timing buffered disk reads: 344 MB in 3.01 seconds = 114.25 MB/sec
It would seem that LVM striping is no substitute for software Raid0.