After evaluating maven-pde-plugin, which one would think would make it easy, turns out not so much.
I've swapped over to using Tycho (because it appears to better support multiple build options, like update sites and RCP apps directly instead of just plugins and features), but that isn't proving trivial even in the most basic sense still.
But, using Tycho 0.9.0 from the ibiblio org.sonatype.tycho groupid (not to be confused with org.codehaus.tycho...or several other groupId's I've run into) you still have issues:
Errors like: "Cannot find lifecycle mapping for packing: 'eclipse-plugin' come up a lot. Looking at the off-chance there is a dependency issue, you are required to use an unstable release version of Maven 3 (as of 7/26/2010 at any rate). Using maven 3.0-beta-1 you now get "Unknown packaging: eclipse-plugin"...so not much help there either.
ANSWER: do not assume the 'convention':
WRONG plugin artifactId: maven-tycho-plugin
CORRECT plugin artifactId: tycho-maven-plugin