Oh yes! I'm always mixing different blends together and have had some success. Half and Half mixed 50/50 with McC 5100 is a favorite of mine. Equal parts of Half and Half, Sir Walter Raleigh, and Heine's Mixture is right good. Adding some McC Blending Perique to just about any Va., Burley, and some Latakia blends can be unbelievably great. What I've mentioned is just the tip of the iceberg of possible combinations.
AJ
You might would like to read about one of experiments in the thread Frankenstein Cocktail.