so, with a sale on, some of Rackham (http://rackham-store.com/)s' Pre-painted plastics maybe worth a scavenge for 54mm bits (http://rackham-store.com/en/at-43/karmans), especially some Mechanicus Praetorians (http://rackham-store.com/en/product/1009)...
Dawkins would be proud.