Update on this: The best rental deals I could find were from Dollar Rent a Car (dollar.com) but their online system doesn't tell you the insurance price (paid at pickup) - just the base price and fees. They have really good deals as far as that goes.
However, www.discounthawaiicarrental.com allow you to search and specify insurance inclusive. It turns out that through them, the insurance inclusive price for Dollar, with zero excess LDW *and* liability, came out about the same as getting my own insurance with www.insuremyrentalcar.com/ (which lacks liability and is insurance, not LDW).
So that was a *really* good outcome. Booked a Hyundai Santa Fe 7 days all inclusive for US$430. Free cancellation, payment on collection.