Been thinking about this post, and poking around a bit. First, the oscillation: Cracked rotors, rotor faces not parallel, or pad material build-up on the rotor surface. Excessive rotor run out is another reason for oscillating feed back. Per Carbotech.
Second: Good high performance "crossover" pads that could handle ocassional track work, and be driven to and from the event safely.
Hawk HP Plus -- Ferro-carbon
Cobalt CSR -- ??
Carbotech AX6 -- Ceramic
Are autox/HPDE pads I'd look at. Good initial bite; high torque; and wide operating temp. range from 50-1000.
All say they are easy in the rotor wear dept. All will dust and may squeal on the street.
I think Bob is right: brake pads leave a film of material in the microgrooves on the rotor. When switching compounds, that needs to be taken off somehow. With the friction and heat generated in hard braking, that's inevitable. Remember brakes are an energy conversion device; they convert momentum into heat, and where the pad contacts the rotor surface, there is some serious friction being generated.
I think you do want to consider rotor wear in selecting a pad, even assuming that rotors are consumables. Unless you are sponsored or something, it would be good for them to last at least one season, and badly scored or grooved rotors are no fun to drive on. Again I found the EBC Yellowstuffs hard on rotors.
Carbotech advises that you do not need to swap rotors when switching from one of their pads to another. I suppose because the materials they use in their compounds is similar, but varies in proportions. So conceivably, you could run AX6s on the street and then pop in XP8s or 10s for track work (200-1350 temp.). Carbotech has a wide selection of ceramic pads, and has great customer support.
Good luck and let us know what you settle on.