Let us first bring out 3.0 before we start discussing about a 3.1 release date.
Imagine you are a mod developer/project leader, this will be you priority list:
1) Last File check, Installer building, uploading.
2) Download test and Content test of the version
3) Releasing
4) Watch our for serious class A bugs reported by the community
5) Bring out (if needed) possbile bugfixes
6) Plan the content which will be in patch 3.1 and what will be pushed back into 3.2 to be able for a faster 3.1 release
7) Doing the changes, creating the stuff
8) Testing
9) Fixing the biggest problems
10) Testing
11) Fixing the smaller problems
12) Testing
13) Can see a release date
13) Last adjustments
14) Last testing
15) Release or accident which will push you back to 9
Every factor here can expand the time we need. If all is perfectly running we can maybe bring it out in a week or two. But who knows the future?