Captain Remus Ventanus (of KNF fame) setting up a chapter during the Astartes reformation. He takes a core of Calth veterans and becomes a fleet based chapter intent on pursuing the remaining Word Bearers.
These are a few of the ideas that I've been tinkering with using photoshop and some templates I found online. At the moment I'm torn between numbers 4 and 5 but I'm concerned they might be a bit too much like the World Eaters - and before you ask, yes I am set on the yellow helmets...
These two are better representations of what they will look like when they're done. I think I prefer the top one at the moment.
FYI these were created on an awesome little program from http://elerd.deviantart.com/art/Space-Marine-Chapter-Maker-136690732