There are a few ways to do what you propose. You could use OP_PICK or OP_ROLL. If you want to be more creative, you can do that with the alt stack as well, look at OP_TOALTSTACK and OP_FROMALTSTACK.
I'm not aware of a better documentation source than the wiki unfortunately. You do know that non-standard scripts aren't relayed though, right?
Thank you! And yes, that much I know... but I might be getting something wrong there; those you mentioned are standard, right? I don't know where I could give that much stuff on to the stack to use ROLL for example, can I give many different items at once to be held on the stack as separate pieces of data? I guess it's just the lack of examples on how to use that stuff. No collections yet? Anyway, thanks a lot. I will keep looking, maybe I'll get something.