The Ms. Pacs like that are a vintage item, having been around forever, however their parentage has been heavily disputed.
Basic cliff notes.
Negative
They are a worst of all world's design that is neither functional (2 player alternating game that requires a chair, no room for the coin box), nor safe (stock Ms. Pac glass just waiting to shatter, no t-molding to protect the cabinet or the clients). It also fails at the stated idea of saving space as it uses more. Cabinet design recycles every component used from the upright. There is no documentation that these every existed, and the cabinet design is more that of a traditional furniture builder than an arcade builder, which is strange since Midway had their own cabinet shop. Every one out there appears to be slightly different.
Positive.
They seem to have mostly surfaced in Chicago where Midway was. There are a lot of second hand conflicting stories about them coming from Midway (sometimes Namco, see how I mentioned conflicting). Some rather trustworthy people in the industry say they are real (Only a slight positive since most of those people have financial interest in one). The bezels on them seem to be a fraction of an inch shorter than on an upright cabinet on at least one cabinet checked.