Thinking about a bass module for the S1.
Many of us have B1's. That's about as small / light as we can expect and still get down to 40Hz, and have appropriate output to match the S1.
We also have A1 amps. All we need is a properly voiced crossover / eq to use with the B1 to get a good match for the S1.
If the crossover was available separately or in a B1 / A1 / crossover package, at a reasonable price, it might be a good seller.
Something similar, in a S1 dedicated and marketed package might sell better than a repurposed B1.
Of course to make this really work good, we need a bass line out on the S1. That would eliminate the need for outboard crossover and eq. If they had done this to begin with we wouldn't be having this conversation.
So maybe the answer is, redesign the S1 with bass line out, redesign the B1 to look like the S1, and put a battery in it.
What if Bose made a new A1 packlite that was battery powered, 250 watts, had cross over built in for the S1 and Compact but retained its normal base line out input for L1s. You could use B2, B1 ect.
Is that what you are referring to O?
edit: added the highlighted part