I am an occasional user to the site, and over just the last few days I've used it for the first time since the preview viewer has been added. (Awesome addition, BTW!) I have an iPod Touch and I don't think there's a lot of utility to a special mobile version of the site. It's reasonably easy to navigate as-is, and the comics viewer works perfectly well, as the Safari browser already allows you to move and resize the scan easily. In my opinion the development time would be better served with other tasks you might have identifed because the iPhone experience of the site is already very friendly.
--Cliffy