Admittedly, I didn't look too closely at your use case, but I believe I've accomplished similar things using css with mgwt. You can check out my app at app.carellaborate.com.
One thing that hung my up was in mgwt the scroll panel has to be a direct child of touch panel, or something like that anyway. If you like the idea of using css instead, I should have more time to help with an example later -- You received this message because you are subscribed to the Google Groups "Google Web Toolkit" group. To unsubscribe from this group and stop receiving emails from it, send an email to google-web-toolkit+unsubscr...@googlegroups.com. To post to this group, send email to google-web-toolkit@googlegroups.com. Visit this group at http://groups.google.com/group/google-web-toolkit. For more options, visit https://groups.google.com/groups/opt_out.