I have gone to many of the Mastering.com produce and mix webcasts and found them to be really great. I saw that the next one on March 17-19 is with Arturia, so likely using many of their products to take vocal and an idea and produce a new song out of it. Each session lasts generally 2-3 hours each day. usually there are two different producers taking the vocal and creating a song with it.
As a bonus, in the past they have given the source material wav files and make a challenge that you can produce your own mix of the song and you can submit it to get voted on for the best tracks submitted. it is a whole lot of fun.
I will post the registration link when they release it. likely in a few days