I have release the source code for the latest released version of Mahjongg Wii on the wiibrew homepage. This contains many changes and additional functions for GRRLIB v3.0.x:

Mahjongg Wii Homepage on Wiibrew

I have not had chance to extract these changes or compared them to GRRLIB 4.0, but though some people may want to take a look to see if there is anything that might be useful to them.

The code has fairly comprehensive comments explaining how to use them.

Please ask any questions you have on the GRRLIB alterations here and I will try to answer them