I don't know about the home replacement. It had options for panel size when I got the phone.
Did not clear any data.
Did it again today! This time, I wasn't using the phone at all but I think it may be related to a widget. Both times the widget was activated. The ScreenModeWidget.
Maybe there's some conflict.
I shut off phone, waited a minute or two, turned it back on and I had double of all icons.....erghhhh.
been there, done that. There are other threads on this. Whatever causes it is elusive. I managed to get it to stay that way long enough to get my phone to the store. Stock phone, never had been rooted (yet

).
The tech there said, back in Jan 2010, that the thinking at the time was that the icons ended up behind the wallpaper and that this occurred with certain wallpapers that weren't "correct". She couldn't elaborate on what wasn't right about the wallpaper but I had gotten it from an app in the market that had all sorts of different categories of wallpaper.
It happened 3-4 times to me then never again. Only the first time did I replace all the icons and end up with them double up later on. They always come back so replacing them is not the answer.