Amazing Ork Conversion Bits from has some conversion bits available that would work amazingly well with Orks.

Currently available through are the following -

Both the Torsos and Legs are currently out of stock but as well as these have sold (they went up for sale on the 6th of April) I imagine they will be making more very soon.

I haven't ordered any of these bits (yet - I am waiting on the Werewolf heads to be up for order) but I think I will get a set of those arms pretty soon - they just look too cool not to.