Just like Internetwork Expert, IE Mentor now has provided Dynamips configuration file to practice their CCIE SP workbook labs. IE Mentor is well known as one of the best training provider for CCIE SP preparation. Their workbook is top of the line and I heard their bootcamp is worth the money too.
All of the information of how to use Dynamips to practice the workbook can be found in this link. The .NET configuration file can be downloaded if you are a registered user with IE Mentor.
Well, actually it's not difficult to make the Dynamips configuration file for any workbooks or any scenarios. But if someone has already made it available, why not to use it? And it's not only the configuration file, this offer also means that even there may not be official technical support available but you know there is someone out there that you can ask when you face a problem setting up the lab. And the priceless forum full of people discussing the setup will come up as well. So I'd say just go for it.