Warhammer 40k: Space Marine Message Board  

Looks like there are quite a few chapter mods for the demo now on the official Relic forums.

forums.relicnews.com/showthread.php?262044-Space-Marine-Custom-Titus-Skins-No-Hud-Addon

No Hud
A Mutton Chops Addon:
Bearded Titus Addon:
Cyborg Titus Addon:
Shaved Titus Addon:
Salamanders Head Addon
Angry Marines Pack:
Black Templar Pack:
Blood Angels Pack:
Blood Ravens Pack:
Crimson Fist Pack:
Dark Angel Pack:
DeathWatch Pack:
Howling Griffons Pack:
Imperial Fists Pack:
Iron Snakes Pack:
Raven Guard Pack:
Red Scorpion Pack:
Salamander Pack:
Space Puppies Pack:
Storm Warden Pack:
White Scars Pack:

Just download the main Texmod link from the top of the page, follow the instructions then d/l and use any of the tex mods you want for the chapter you prefer.

I'm laughing at the addition of the Angry Marines.