Recovery to backup point

Hello,

It seems that Everyone welcomed the following functionality, and I also want 
it to solve some problem.  But this doesn't appear to be undertaken.

Recovery target 'immediate'
http://www.postgresql.org/message-id/51703751.2020208@vmware.com

Is there any technical difficulty?  May I implement this feature and submit 
a patch for the next commitfest if I have time?

Regards
MauMau