Just thought I'd confirm that there are themes that will flash over the top of the pre rooted Roms that ironass wrote a guide on.....
This is no dummies guide(except it's written by a dummy/while sucking a dummy :-s) just a quick list of what I've done and a link...possibly updated later with a few other links...
Firstly I'm on djembys(sp?) Mf5 based stock Rom, I then flashed the deodexed file available on the xda page(I'm not sure if it would have been required or not, but I figured it's better to be safe than sorry!
After this,I downloaded vertumus's theme from here
and flashed through cwm....however I personally like to have a battery icon with the percentage within, so I downloaded a battery icon from the list of 600(I'll get a link later) and flashed it separately....I do however have Rom toolbox pro, so actually backed up the battery icon first, then flashed the zip for my new icon :-)
Prior to all this,I did of course do a nandroid
:-) I'll give a few more links tomorrow and possibly even a screenshot.
As you can see, I've not quite got the hang of being able to upload pictures properly as I always have issues with sizing...any way, here are a couple that have been cropped almost to extinction.Lol I will also add the link to the battery mod as you can see I went for blue Android, but there are 600 to choose from! Also the theme changes the settings menus to be all black with white writing, similar to that on a nexus device/ cyanogenmod Rom! Personally I'm not bothered about the settings menu, but I do like the blue icons :-)
Here is the link for battery mods http://forum.xda-developers.com/showthread.php?t=2280597&highlight=battery+modific ations
I had better mention that other themes do also work, important thing is to ensure that it is compatible with the firmware your running,I had also tried a black chrome theme which didn't quite work the way I had planned,With vertimus's theme the dialer etc are also themed :-)
Let us know what theme you go for and any combos :-)