While Apple hasn't announced anything yet, I have to think that a lot of iOS APIs are going to show up in Lion to make it easier because, you're right, it's very non-trivial now. I mean, I'd rather port a UIKit app to AppKit than a Windows Forms app. But there are a lot more differences than there have to be.
While Apple hasn't announced anything yet, I have to think that a lot of iOS APIs are going to show up in Lion to make it easier…
Prepare to be disappointed. Technology stacks aside, if the interaction models between desktop apps and multi-touch interfaces were in any way relatable, UIKit wouldn't have been invented.
If you want to write a Mac app for the new store, you'll be using AppKit.
