@RussJ - So commentary on other things aside, just know that even the highest-powered poly's won't be all
that much more powerful than BBO – you might get a few percentage points more explosiveness. Whether that's enough for you, only you will know. One example might be something like
Toroline O-Toro, which will be noticeably more supple and gut-like in its rebound response than BBO, and although it might not be quite as durable as BBO, if you're pretty much not breaking poly at all, and it takes you 2+ months to break a multi, then I doubt you'll have any issues with O-Toro's durability for the better part of a year.
That said, I think you might want to explore look at different string materials. Since I presume your distaste for hybrids comes from wanting to keep things simple (I get that), then I would highly recommend looking at a synthetic/poly fusion string, which blends both materials into a "hybrid", all in one string, to give you a good amount of poly-like control, with the higher power and "play it until it breaks" benefit of synthetics. Good examples would be:
Tecnifibre Triax,
Tecnifibre HDMX,
Yonex Rexis Speed and
Prince Lightning Pro, all of which have varying levels of poly in them. From lowest-powered and most poly-like to highest-powered and most synthetic-like, the progression would go Triax -> HDMX -> Rexis Speed -> Lightning Pro.
Beyond that, I have some other ideas, that mainly involve hybriding, but will hold off per your stated preference for the time being.
Hope some of that helps.