This is a timely post, I just spent some time yesterday doing the same thing for the exact reason. (certainly no less appreciation to those who have written all apps that make the PB useful)
As mentioned you can rename the .roku file for a given app. You may also have to change something inside it as well. I'll use mythrouku as an example. I wanted to change it to Watch TV.
I renamed the mythroku.roku file to:
Edited it and changed the same inside on the first line that sets up the path to the cooresponding .app file. You'll see I escaped the space in the name, that is put a \ in front of it.
SXPATH=`echo "$0" | sed 's/\/Watch\ TV.roku$//'`
"$SXPATH/mythroku.app" -settingsdir=DIRECTORY -backend=192.168.1.2
I also renamed the icon (.png) file to:
I also went and found some new icons that match, yes I was a little bored. The ideal icons size, if you choose to replace them or build your own is 96x96, at least that worked for me.
Does anyone know who to change the sort order of the icons or at least what it based on?
Here's what mine ended up looking like: