Thank you for the very positive responses!
Note that I didn't sculpt the nice looking upgrade parts, I just made them work with the
GW kit. =]

I put some Ready Base Mediterran Soil on the bases and added some tufts.The idea is to keep the basing easy and convenient to encourage my friend to base his army as soon as he's done painting his squads.
This mix doesn't have any grey in it and does contrast very well with the models in this dark silver scheme.
I'm curious if anyone has an idea for any scattered items that could go with the base as something random found on the ground the models are walking on.
I know they make deamon skulls in the
GW skull pack, but I figure those are dumb, since the deamons are supposed to disintegrate upon death, rather than decay like living matter would.
Any ideas? What do you guys slap on our
GK bases?