I've been looking into report definition customization extensions (RDCE) in SQL2K8 recently and I've been at a loss to find much documentation or even chatter on the internet about it.
MSDN has a brief overview: http://msdn.microsoft.com/en-us/library/cc281022.aspx
And the sample report from this book http://www.amazon.com/Applied-Microsoft-Server-Reporting-Services/dp/0976635313/ref=pd_bbs_sr_2?ie=UTF8&s=books&qid=1221629676&sr=8-2 is something, but I was wondering if anyone had real experience with this and how it worked out for them. And if anyone has other references worth looking at I'd appreciate it.