You'd likely need the Pro version so you could take advantage of the solid tools, and you could probably find a Ruby coder to build this for you... if you didn't want to create it yourself.

I've had some custom scripts written for me from some users on the SketchUcation forums.

Also, the TF Rubies are great for creating mortise and tenons, and any relatively simple TF joint - but due to the limitations of the modeling in SketchUp (its a surface modeler, not a solids modeler) - the program can only 'cut' into 1 face at a time... thats why splines and rafter feet and other joints are hard to build in SU using the TFRubies.

I rarely use the rubies for work - as most timber framers can follow coding / instructions for joint callouts. I simply illustrate the typical joints, and then draw / model the complicated bits as needed. I rarely do 'stick' drawings for my clients.

If you are just illustrating these, don't use the TF Rubies... just draw them. You might even be able to draw 3-4-5-12 different 'end conditions' in different log sizes as components) and then just stretch them out, mirror for the opposite end (if the same), or paste in a different end as needed.