It's reasonable....but what's going to be key here is the coil characteristics & how you connect them all together. For example an inductance figure of 1mH (circa 150 windings) & a DC resistance of 8 ohms seems to be the ballpark for a general purpose driver ...the inductance figure is derived (in the main) from the number of windings your driver coil has.
Therefore if you want to connect say 12 drivers in series, you'd want to shoot for 1/12th of those figures per coil (therefore each individual coil should be about 0.66 ohms & 83uH!). You'd need to experiment with differing coil gauge as you'd be beating a trailblazer's path there! My gut feeling is that a coil of 83uh, that the wire would need to be very thin to be able to get 150 turns - so thin, I reckon it'd not handle the current needed to get a higher frequency type string 'excited' sufficiently.
I'd also have to assume that trying to span/excite so much string real estate with one 'virtual coil' (12 mini coils in series) would need a fairly chunky driving amplifier.
if you don't need individual control per string (as per the EMPP), then I'd go with your 12 drivers connected in parallel or a combination of series/parallel (You'd still need to be careful with your coil characteristics, but they'd be more do-able vs pure 'series' connection)
Well, I tried a couple more designs. One was a thin steel core, 4" long, wired with 30 AWG to 8 Ohms, solidified with PVA glue, with a ceramic block magnet attached to the blade.
Another was like you suggested, wire wound around a plastic sewing bobbin, again potted with PVA glue, with a bolt in the middle of the bobbin and a neodymium magnet attached to the bolt.
Both worked okay, not great, although using the glue eliminated the direct sound I had been getting with my earlier attempts.
However, neither was nearly as good as the Radio Shack Miniature Audio Output Transformer, I cores removed and E cores aligned, with a neodymium magnet attached. This driver is by far the best of those that I've tried thus far.
So...thinking aloud, would it at all be reasonable to wire up 12 of these transformers in a combination of series and parallel like:
7 in series
3 in series
2 in series
and those three groups connected in parallel?
With 8 ohms per transformer, that combination seems to yield a total impedance of 8.1951 ohms. Of course, this doesn't consider inductance.
EDIT: I had incorrectly assumed that the transformers had an impedance of 8 ohms. In fact, after measuring, they have an impedance of 1.5 ohms each! So, how does that effect what I should do?