Bummer... I was hoping to see some more innovative cab builders joining the discussion here. I've seen countless vids of folks buying those Arcade 1ups then 'upgrading' them... reminds me of that old saying 'like pouring perfume on a pig'.
In fact, checking one out at the local Wal-Mart made me certain that building my own machine was the way to go. First off, it's like three feet tall, and when I grabbed the joystick, the ball fell off... not a good sign. If you're willing to spend $300 bucks on one, consider that it only costs a little bit more to go first class!
I've had a blast with my custom cab but can't seem to stop thinking of ways to improve it.
Most recently, I've added an (Aimtrak) recoil gun and plan to get another one for 2 player action. Loads of fun! Ultimarc also offers a 4/8 way stick that has a powered switch to change it on the fly. I'm now thinking about trying to adapt one to my tankstick.
C'mon guys (and gals too)... get busy on your machines and post those photos for fellow Retrorommers to enjoy!