Check with CH4D they have a large selection of Wildcat dies on hand. Over the last couple years I have contacted them and they have had dies I need on hand. Had them on my reloading bench writhing 3-4 days. .375 Raptor, .243 LBC, 25-06 Ackley, 22-284.
As mentions above. Just order a 30-06 bushing die and use the proper size bushing. As for the seater. Just purchase the proper seating stem for the 6mm bullet you wish to shoot and instal it in the seater die.