As a starting point I'll say the Suhr Pete Thorn HH wiring seems really versatile and easy to me:
1: Bridge humbucker
2: Both humbuckers' inner coils ("Strat notch")
3: Both humbuckers
4: Neck humbucker (as opposed to typically placing this in position 5)
5: Neck outer coil ("Strat neck" sound)
Push/pull: Series/parallel switch for bridge humbucker
That's quick access to all your most in-demand sounds.
Overall I can't think of an improvement on that 5-way layout, but curious to hear other ideas.
With the addition of a second toggle or second push/pull, there's three key approaches I can think of:
1) Use second toggle as a series/parallel switch for the neck humbucker, mirroring the application of the bridge push/pull in the Suhr PT
2) Use the second toggle to make available "binary switching" of the bridge humbucker, where the two switches can give access to either coil, series humbucker, or parallel humbucker. This can make available a Tele-style hot single tone. This might be most interesting with very hot bridge humbuckers, where one coil could give a convincing Tele tone, or parallel mode could be a good low-wind PAF tone
3) Use the second toggle as a simultaneous series override and phase switch. I don't normally find out of phase sounds to be super useful, but wired in series the usability improves. Another bonus to this could be using the neckward coils of both pickups, which would be hum-cancelling if wired out of phase.
Downsides: no availability of the other hum-cancelling single coils option of both pickups' outer coils (i.e. "Tele middle" tone)
