There is a IETF draft specification that is likely to become a standard for specify URL patterns called "URI Templates" [1]. At a high level it differs from current Permalink configuration by using braces "{}" instead of percent signs "%%" as delimiters:
/%year%/%monthnum%/%day%/%postname%/
/{year}/{monthnum}/{day}/{postname}/
Doing this will prepare for interoperability with other future URL-related management software.
[1] http://www.ietf.org/internet-drafts/draft-gregorio-uritemplate-00.txt