[plug] can software raid change its configuration on the fly

[William Kenworthy]

Is this practical

Set up a new single hard disk as a basic software linear MD with LVM and
reiserfs
The I would like to add a second disk in a few weeks to this using
linear, move the data around, change to raid0 and finally adjust the
partitioning (without losing data).  

This is actually my ultimate aim - to get back to a raid0 setup, but a
disk failure means I need to do it before I am really ready.  So can
software raid change its configuration on the fly - how as the docs Ive
found just hint that it can be done, but dont say *how* that I can see.

Is there a better way?

I am also looking at getting 200G WD JB sata drives, these seem good
value/cause few problems at the moment - right?

BillK