Haibo recently posted about nullbox impacts on reflection.
Haibo is a test engineer on the Managed Services Team (MST), the portion of the CLR team that focuses on dynamic programming features. MST owns such things as reflection, delegates, and generally any feature that is used to dynamically interact with the CTS.
Other interesting MST blogs include Jim Huginin, Joel Pobar, and Kathy Kam. If you want weak delegates (or similar features) in the next version of the CLR, feel free to send any of them exorbitant amounts of email.