I thought I'd start a new thread for this, because I've read several posts regarding this topic, so here it goes.
As of 7th august, 2010, you can use your own customized icons with the updated ru.launcher (if somebody doesn't know yet, it is the launcher that comes with the softroot).
You can download the updated version here:
I have also written instructions on that wiki page on how to use your own icons. (Along with the full icon name list on the bottom part of the page).
I tested this version myself and everything worked just perfectly. If you encounter any errors or require assistance, just post here, I'll look into it.
I have created my very first icon, which replaces nook market's icon. (As far as I know, every downloaded
application has a very ugly looking icon in this launcher, that is because those icons were made solely for the other launcher (nookLauncher)) So I intend to create an icon for every downloaded application