Latest video is up! Episode VI covers an aspect of customization I would love to see in Destiny. Please let me know what you think :)
originally posted in:Dear Bungie
To support your theory, look at the Duke MK. 44, on the drawing board. You can see the customization there as you described. The red version is the same as the silver version, without the slide attachment on the bottom of the receiver. The trading card is the silver version with the red skin and the attachment added, one weapon in customizable versions. The version with the added sights and receiver attachment and decals is an example of the this customizable ability.