I believe Bubble Bobble was a JAMMA game (I could be wrong, and I'm sure ill be corrected quickly if I am) and if it is JAMMA, it would be very easy to convert it to ST.
You're going to have to custom build a control panel obviously, which isn't too difficult - The only thing that might inhibit that is you're going to have to make things pretty tight to fit 6 buttons each on that space