This could be nice, and it could get me to start using iTMS. If they put it in a lossless format with DRM (which seems likely), I might still sit out, though. Right now my policy is not to pay money for anything that is either encoded in a lossy format or includes DRM. I might be able to make an exception for the DRM provided it isn’t too restrictive and I could encode to a lossy format (which doesn’t seem likely), but I would have to think about it.
What I expect to be able to do with my lossless music is to keep the originals as backup, burn them to a CD, and rip them to MP3s for my iPod. If I can do all of those things with iTMS lossless, I would consider overlooking the DRM.