When we spoke to Gary Stern way back in January at CES, the pinball exec let it be known that his was the only company currently producing pinball machines -- and while that may be accurate so far as actual shipping systems go, there are a handful of startups looking to get into the game. One of the more compelling examples we've seen is the offering from Multimorphic, a local company showcasing a prototype at SXSW Interactive's Game Expo. The P3 is interesting for a number of reasons. First, and arguably most importantly, is the modular nature of the machine. If you take a look at the (still unfinished) sides of the cabinet, you can see a big slit down the center, where the top can be lifted off and replaced -- since the ma