Lock Calendar is available through Cydia (BigBoss repository), and will do what Intelliscreen does with regard to your calendar on your lockscreen. Actually, I prefer its implementation over Intelliscreen's.
Separately, I just saw something on Cydia this morning called "SweetMail" (Modmyi repository) that will do the same, for unread e-mail messages. It looks like it can only be configured for a single mail account, though, and I don't know if it can be used at the same time as Lock Calendar. I installed it but then decided not to configure it because I was hesitant to give an unknown program my e-mail username and password.