Can I migrate Linux RAID1 to RAID5?

[christoph at linuxsoup.com]

Hi eveyone,

I've got some time on my hands today (expecting 4-8 
inches of snow), so I thought I'd play with my RAID config.

Does anyone know if the Linux RAID tools porvide a mechanism
to migrate an existing RAID1 (mirror) to a RAID5?  I
bought anther disk and would like to add it without
requiring a reboot.

Also, are there any technical show stoppers to putting
the root partition/filesystem on a multi disk RAID5?
I can think of a couple "best practice" reasons not to,
but this is a home machine... so those don't really apply.

Thanks