I think the option should be there, however I probably wouldn't use it.

I'm really curious though as to if I can use a Storm Shield and say maybe a plasma pistol, or some one handed ranged weapon.

THat is a good point. I keep forgetting about the shield for infantry

I don't see why you wouldn't be able to. After all, if you can use twin lightning claw powerfists why couldn't you dual wield other melee weapons?

Using shields with ranged weapons is not new to Warhammer 40k either. Astartes are known to use shields with plasma cutters and bolters/bolt pistols for boarding actions/breaching.

Aaaaand how about....2 SHIELDS? One for blocking, the other for even MORE blocking? Or shield bashing

On serious note, dual wielding would be cool. Perhaps test it with only allowing it for some special classes, like perhaps Berzerker(2 axes) or banshees with 2 power swords.

Can I wield two Thunder hammers then?

I hope at start we can wield 2 pistols though. This will be perfect.

a Space Wolve with 2 Axes would be unstoppable >:3

I think that wouldn't be possible? Considering how heavy they are and the Infantry usually need two hands to use them. Unless the Devs make smaller variations of the Thunder Hammer? But I dunno

A Bolt Pistol with a Plasma Pistol
Or Melta Pistol with Plasma.
the possibilities are endless

Isn't that an Inferno pistol?