You would think most of the developer community has never heard of cross compilers.
From a technical standpoint, you do not need a Mac to generate application code that would run on the iWidget.
What you need is development tools that run on whatever hardware/software platform you own, that will compile code for the hardware/software platform you want to develop for, and a way to then send that compiled binary code over to the target for execution.
Now whether that solution exists, I don't know. I'd expect, in this 'open source' day and age that someone would be working on a cross-compiler dev environment that lets you build iWidget code and transfer it to the iWidget for execution and testing.
Whether any of that violates a license agreement is a separate issue that I'm not so concerned about. If I ever got to the point of developing an app that has promise, then I'd subscribe to the dev network to gain access to the closed store environment (as a hobbyist)