Look Before You Leap.
We are all aware, I believe, of the nature of canine congress. Thus, should we ever muse on the mechanics of creating a cross-breed, we might have a notion of what is practical and what goes where, so to speak. But, unless I'm just peculiarly ignorant on this matter, I would suggest that we might well have a faulty vision.
It turns out that breeders cross a male of a smaller breed with a female of a larger breed and not vice versa as I might have guessed. The reason is not simply to make the union more visually comical, but rather to ensure that the puppy is of a size that is manageable during birth.
Obvious, isn't it? But all too often, we focus on the creation of something and not the consequences of what we have to deal with down the line. Your latest marketing initiative may seem like a great idea, but it only is if you've ensured it doesn't cause you pain in the future.