From http://www.wdwinfo.com/wdwinfo/dining/disneydining.cfm
The Wave:
Braised Chicken Pot Pie - Made with peas, mushrooms, and carrots, topped with thyme pastry. - $19.99 (oosted 6/08)
From allearsnet.com
Raglan Road:
Pie in the Sky - chicken and wild mushroom pie served with a rocket lettuce salad $16.95 (posted 8/08)
50s Prime Time (lunch only):
Chicken Pot Pie - creamy mixture of chicken, mushrooms, carrots, celery, peas, and onions topped with a flaky pastry $16.99 (posted 3/08)
I think the dish with the mashed potatoes is Shepherd's Pie, available at Raglan Road and possibly Rose & Crown (and maybe other places) but it's made with beef.