A dummy unit? Uh-uh, not gonna work. In my philosophy, ALL locomotives (including diesel B-Units) should be powered (no dummies allowed) and capable of independent operation (in actual operation however, B-units, like their prototypes, are essentially "slaves" and not used except in a lash-up with a cab-equipped unit). In other words, eschewing dummies makes the motive power fleet more flexible, IMO.
Recently MTH announced the introduction of a single-channel TIU, which could be theoretically smaller, making battery conversions easier.