The ShortURL plugin provides short canonical permalinks to your posts and pages similarly to WordPress.com via its WP.me service.
RevCanonical is not supported by HTML 5 and it seems that Short URL is getting wider support by big blogs such as Ars Technica and other sites such as PHP. We will closely monitor the developments and implement the winning specification.
Yes, in the near future. Actually, third-party providers are already supported by the
Short URL custom field, but it's not automatic and you have to shorten the URLs manually.
Yes and this will also eliminate the dash in the URLs.
Yes. The dash-based one will continue to be the default one though.