the earliest i've seen is october 15 (penn and yale). there may be others, though... yes, this means letters i am assuming, though they will still get your letters if you have them in by nov 1 since they'll have to download the dean's letter then.
some schools start looking at applications early -- buffalo comes to mind as offering early interviews when i applied the first time. i don't think most look at them until after the dean's letter comes out. most prelims look at them as they come in.
wondering about suny downstate. it is non-eras, right? how do you get an application? they have all these old webpages when i do a search for their derm department. i sent a letter requesting an app a few weeks ago but never heard back.