At some point I will complete this section. I have been successfully running software RAID and LVM for some time, including using an LVM LV for my root partition where the LV is on a RAID PV.
However I have recently come across a problem I thought I would document. With the etch release of Debian and the feisty release of Ubuntu there has been a change to the boot process. Previously both used initrd-tools whereas they now use initramfs-tools. I have always specified my LVs as /dev/vg/lv, including on the root= kernel parameter. This does not work with initramfs-tools which expects root= to be specified as /dev/mapper/vg-lv.
Also, on Ubuntu, if you put /var in its own partion, then your root partition must contain mount points for /var/run and /var/lock