“(As an aside, I hope someone does create one, and soon. I want to write an OS X app, but don’t want to pony up the $99 developer fee until I’m certain it’s close to ready for market.)”
You can get all the OSX developer tools free, you only need to pay the $99 if you want to sell through Apple’s stores, or download an iOS app to an actual device rather than a simulator.
Just register for a free developer account. You’ll have access to the XCode 6 beta.
I checked, and with a free dev account, no I can’t, at least not as of this morning. I do have a friend who’s a registered iOS developer, though, maybe I can get the Xcode beta from her.