First up is the CO and squad. I based him with so that he could strike a suitable heroic pose, complete with evidence of the effects of the Emperors Artillery.
Don't worry, that building fell on you for the greater good.
The urban themed basing is accomplished pretty easily by just gluing on random bits of scrap structural shapes from other projects. painting that a rusty color (bestial brown, with a blazing orange dry brush, and drybrushing the gravel with various shades of grey.
Next are the first two vet squads. Each squad has a different color drybrush on the hat. Differentiating the squads was a 'Paint Point' at the NOVA Open. I've since discovered that it also makes my life easier during deployment and pack up.
The Autocannon Teams were build by grafting a plastic autocannon onto the arms of the heavy bolter models from the Vostroyan Infantry Squad box. I used some styrene rod to make the spent shell casings
Now the inevitable Melta-vets. GW never made vossies with melta-guns so I converted the flamers.
Finally, the motor pool:
And artillery support