I have been painting yesterday - or rather today - until 4am to finish 4 new Iron Warriors, 7 special weapons and 2 arms for a Champion, but here I am, with everything finished.
Because my next tournament list will include a hell of a lot special weapons (woohoo, 2 squads of Chosen CSM!), I had a look into my glass cabinet and was astonished I only had 2 Flamers, 2 Plasma guns and 2 Melta guns... So I raided my bitz box and found enough special weapons and parts to assemble another 4 Iron Warriors. But I did not glue the special weapons to the arms - instead, I drilled holes in the undersides of the weapons and the right fists of the CSM (quite a fiddling!). Some super glue and carefully pressing the magnets into the holes (mind the magnetic poles!), I had 7 CSM with fully magnetized weapons.
They can all be swapped:
I did the same with the arms of my second Champion, so I can give him various equipment:
I hope this was a little bit of inspiration and help for you. Because why should you paint more models than you need when you can simply give a certain amount of painted models the wargear you want to field? :)