Just how small MUST the measurements be?
I've never heard the Minivee, though Ive seen a couple of satisfied posts. The Dynamo has a lot of fans. However, when I auditioned it with HT material, it just really lacked both output and extension. I know setup is everything, but I've heard it in more than one room. The Dynamo tries mightily for its dimunitive size, but if you can afford having a larger sized sub, I would guess that you can get better performance for the same money. Perhaps even a LOT better performance, depending.
The lack of output and extension very well might not matter so much if this is for a music system, if you are listening to string quartets, and other music without bombastic bass. Folk guitar-singers, etc.
If for HT, I think it would benefit you to state what the maximum dimensions of the sub must be. I won't necessarily have the magic answer, but someone just might.