Cornell University has a huge apple farm, they are working on a bunch of varites with different resistances. I would also check out trees of antiquity,
Trees of Antiquity They have write ups of all the different apples.
I am using Cummins Nursery to buy 5 goldrush and 5 enterprise as part of my CRP planting that will begin in the spring.
Cummins Nursery | Home Page I found that cummins nursery to be very knowlegable and very willing to work with me to find the trees that would do best on my soil type.
the enterprise is a Tree that is spreading and vigorous. Immune to scab, resistant to fire blight and cedar apple rust, moderately resistant to mildew.
the goldrush is Field immune to scab, highly resistant to powdery mildew, susceptible to cedar-apple rust, moderately resistant to fire blight.
I wanted trees that would be as low spray as possible.
btw, for cidermakers, there is through wyeast (a yeast company) a seasonal cider yeast that they make.