I don't beleive the P2 boxes are much smaller. For small HD box, Quantum is the way to go.
VMS is about the same size as STB, but IPCs are quite small. Around the size of the digital adapters.
The P1's are the older silver boxes. The P2's are the newer black ones. The P2's are taller then the P1's, but are not as wide, but the difference in size between the 2 isn't that much. Are the P1's all that they had in stock to give you?