The steel (I might use copper screen soldered to the PCB's GND-plane, but even aluminum screen with pressed contact, would work) screen is a capital idea for managing EMI, yet, at distance, it won't be visible at all, and a fine screen won't even be very visible at normal reading distance. You could use expanded metal, or a coarse-mesh hardware cloth as a shield, as it might allow the segments to be unobstructed by the shield.

Further, if you are really serious about managing EMI, you'll use a grounded pads-only layer on the top of the PCB to which you solder the screen or expanded-metal shield.

Kai's also right about the "creative" multiplexing. You don't have to drive six adjacent display groups from a single driver. YOu could pick and choose, based on layout and "artistic" preferences. This will conceal, somewhat, the multiplexing scheme. You probably have enough time in which to make the associated decisions and reordering of signals.

RE