I understand the pain in locally building all the SNAPSHOT maven 
dependencies, so I'm gradually moving away from requiring snapshots.
So right now, the only SNAPSHOT dependency you need is the 'jruby' 
branch of Jenkins. I've capture this in [1].
I'll be working on removing this SNAPSHOT dependency as well. Some of 
the changes in this branch needs to go into the trunk, and some needs to 
move to the ruby-runtime plugin.
[1] 
https://wiki.jenkins-ci.org/display/JENKINS/Jenkins+plugin+development+in+Ruby
-- 
Kohsuke Kawaguchi | CloudBees, Inc. | http://cloudbees.com/
This will be a part of 1.426, and at that point and onward, hopefully we 
won't need any custom build of Jenkins to do the Ruby work.
That's why the timeline is bit off. My apologies.