ReTweetie adds legitimate retweeting to Tweetie Mac
One of the biggest frustrations with Tweetie for Mac is the lack of legitimate retweeting to your followers. While it's understandable that the developers have been a tad busy in the past year, it doesn't seem all that unreasonable to at least issue an update to include a very basic Twitter function.
Developer Nick Paulson solved this by writing a plug-in called ReTweetie. The ReTweetie plug-in requires a download of SIMBL, which is a free bundle loader, and the program itself. After relaunching Tweetie for Mac, hit "repost" and enjoy full retweet goodness.
As for Tweetie for Mac itself, development on version 2 was alive and well as of October.
Many thanks to @AndruEdwards!