Here are links to websites which sell pre-heresy conversion bits that will help you make standard heresy marines. Enjoy!
For terminator shoulder pads:
For jump packs:
For marine shoulder pads:
I will be making an order at some point this month from both sites so if you are interested let me know and we can make a bulk order.
In one of these two sites I think they also mention the possiblity of commision work. That is to say that they may modify shoulder pads to specific markings. So I may be asking for scarab and bruning sun shoulder pads.