ZachLthere's the Sd-2 that go for a similar price as the MD Plus. Number of drivers hardly matter as much as the tuning and crossover system etc that are in place.
Also, you did not specify your price consideration. I merely answered your question with my best suggestion with regard to the shape of the housing.
ZachLShure, Westone, Nuforce, etc. that have a teardrop shape would be your best bet. I can sleep in those pairs and lay on my side in bed just fine. The MD+ may be a hair taller but I can lay down with them much easier than my Nobles.
NewType88Honestly I've been sticking with my skullcandy bluetooth ink'd wireless they're barely noticeable. My TFZ series 5 exclusive stick out a little too much for it to be comfortable sleeping. I might eventually try out those headbands with speakers but that seems uncomfortable. I've owned winter beanies and hoodies with "speakers" built in and it's a hard circular disc on your ears. Most of the time I leave my desktop speakers on if I don't have to worry about being loud.