I had a very positive result recently pitching multiple yeasts after thinking I was experiencing fermentation lag due to low cell count. Turns out I had a cracked and leaky airlock stopper. It could be that the original culture did all the work, but after pitching two more differing strains of dry yeast and then mixing the two 5 gallon fermentors I had, of course a raging primary and some very fun black IPA. The dry yeasts were SafeAle (05 2000ml starter), then a Notti followed by a Lallemand west coast.
I'm planning to remake the recipe and actually considering making a blended yeast starter again. Any thoughts?