I have 20 space marine terminators from the Assault on Black Reach and Dark Vengeance sets and NONE of them come modeled with the very common and popular thunder hammer/stormshield combo or cyclone missile launchers. It can be very pricey to bits shop around for thunder hammers, stormshields, and cyclone missile launchers to convert these to, so I decided to just build my own. The hammers are actually from my Mantic Games dwarfs army and while not quite as nice as the actual piece, they'll do just fine. Now the actual space marine storm shields I think just look too small so I made mine much bigger. I just used a bit of plasticard for them. I do plan on adding some decorative detail and iconography to the shields to spice them up a bit. Anyway, it's pretty unmistakable as to what they are modeled as and that's what matters.
The missile launchers I built mostly out of those red plastic rulers that come in the warhammer starter boxes and a few paper clips. I think it will look pretty good once they're painted.