I am running a D&D 4E campaign, and I particular enjoy that a lot of the 'man-made' spells that the PCs encounter—when for example, raiding wizards' hideouts—can be described as "you can get a ritual for that if you wanted", or "anything they can do you can do too if you put in enough effort". So when creating plotlines and locations, I try to come up with a 'ritual-explanation' for as much as possible.
My question is, are there any rules or guidelines for creating rituals (and magic items) that are not described in the various sourcebooks? I have two examples, but my question is not restricted to just these:
A paladin PC wants to forge his own magic shield, and I don't want to choose one from the sourcebooks as it'd lose its uniqueness. Is there an easy way to determine what stats it could have for a given level?
A wizard NPC is going to show the PCs a faked 'vision of the future', i.e. a pre-made film. What level and cost would this ritual have, were the PCs to want to learn it for themselves?
Thanks in advance.