As matt had mentioned, you might want to look at the Union. This has many of the features you're looking for. It has the strata track and part PVC/part wood core, which keeps the rocker line stable to pop great off the wake, and it also has ABS sidewalls and enduro base, which makes it extremely tough for taking abuse at the cable. Some friends of mine ride this board for both boat and cable and have been very stoked on the results.
While this may not solve all you predicaments in one fell swoop, its certainly an option worth looking into.
And as far as the nova core boards being too soft for cable - that is certainly not the case. They are much stiffer and stronger than the bio core, but the catch is the warranty will be void. Since no board is warrantied after hitting rails, most people would rather slide an old beat up junk board that is already out of warranty anyways. The nova should hold up to the same amount of punishment that a bio core would, its just that no one slides them cuz of how expensive they are and it kills the warranty.
Also one last bit of personal experience. A few years ago, I was hell bent on finding a board that I could legitimately ride on both boat and cable, even though the nearest park was 5+ hrs and my boat/cable time was about a 90/10 split. I rode the Conspiracy, which really did excel in both areas: awesome pop on the boat and tougher than nails at the cable (still my current cable board even with a small crack by the rear boot, after 2+ years of sliding it keeps goin strong). After switching to the Franchise for the boat board (much faster and a tad looser), I realized that I didnt notice the differences on the conspiracy at the cable park other than the obvious (speed and grip) but it wasnt enough to significantly affect my riding on cable or when i got back to the boat. Now I am happy to beat the tar outta the conspiracy and have been learning new tricks all spring on the Franchise, needless to say, stoked on the outcome.
Hope this helps out.