May I offer some advice and resources on painting/heraldry for you and other resources as well for making your White Scars really unique visually.
First, the standard wiki articles on them:
http://wh40k.lexicanum.com/wiki/White_Scars
And:
http://warhammer40k.wikia.com/wiki/White_Scars
Great resources for history and fluff. Interesting to note that White Scars Librarians are known as "Storm Seers", cool bit of fluff about them.
Next, painting: (Taken from the second link I posted above)
"Chapter Colours
The White Scars' Power Armour is predominantly white, with red trim. This has only varied slightly since the Pre-Heresy days of the V Legion. Apothecaries of the White Scars have their entire armour painted red save for the backpack, right shoulder and the helmet which are all white and have a red vertical stripe painted down the centre of the helmet. The red-coloured squad specialty symbol (Tactical, Assault, Devastator, or Veteran) is indicated on the right shoulder guard while the Chapter iconography is painted on the left shoulder guard. Squad markings are displayed on the left knee plate. Sergeants also bear the company markings upon their armour's right greave. White Scars Bikers' helmets usually display Chogorian tribal markings.
Chapter Badge
The White Scars' Chapter badge is a stylized red thunderbolt with a horizontal yellow bar behind it, exemplifying their style of combat and echoing the facial Honour Scars all members of this Chapter bear. Members of the White Scars' Scout Marines Brotherhood are permitted to wear the thunderbolt on their shoulder plates, but an obscure piece of Chapter law states they may not have the horizontal bar, an honour only given to full Initiates."
Lastly, Have fun with it! Games workshop sells a White Scars upgrade pack with bits to make a commander bike unique, but you may be able to find a source for round mongol style shields and such from an alternate company and just build something up that's uniquely yours.
I hope this helps, and do keep us posted on progress as you make it!
Take it easy for now.
-Red__Thirst-