JoeM is correct, the "creaminess" of stouts is due to the grain bill and not the yeast type. Oats in particular are used to add creaminess to brew. The nitrogen sparge may inhance the affect due to the smaller bubble size, but it is not necessary. If you are doing a straight mead, it may be difficult to duplicate this affect without adding grains. You could use a non-grain, non-fermentable additive like malto dextrin. This will increase the mouthfeel, but you probably won't achieve creamy goodness.
Peace.