Why would you use Creative Commons instead of another licensing method for your authored RPG material?
Do you know of successful and unsuccessful companies that have used CC that would be willing to share their experience?
Nota bene: This is not asking for legal advice. If I needed that, I would be talking to a solicitor.
You would use Creative Commons because it's a solid license people use frequently in other forms of artistic endeavor.
A number of RPGs use Creative Commons, but probably the most successful is Eclipse Phase.
Many RPGs prefer the Open Gaming License (OGL) simply because that license came to be in the RPG realm and they are familiar with it. It is not necessarily the best fit however - it does not have the fine grained choices CC has. With Creative Commons you can differentiate between just giving you attributions, whether changes are allowed, whether those derivations may be commercially used - the OGL lumps all this into one default loadout. The OGL also requires a page of legalese in every document unlike CC. The OGL is also generally stigmatized as a d20 license among people that don't know better, and also due to its history being created by Wizards of the Coast, risks being caught up in industry wars (WotC originally called out the OGL in their new 4e GSL as part of a 'poison pill' provision, since removed.)
I'd primarily do it (licence rpg materials using CC) to reach and involve a wider audience - that is, for marketing purposes. Why CC instead of other open licenses? Since you're not asking for legal advice (which I could not give you anyway), I'd say that its primary "selling point" is that a lot of people are already familiar with it online, hence it would provide a basic trust even for those who don't know the rpg-specific licences.
As for companies willing to share, I have no idea, but you might want to take a look at rpg.net's list of CC licensed games and visit some of the sites linked, check if they have forums or other ways to contact them.
