For instance, I'm trying to find several episodes of The Office (episodes 5 & 7-11 of season 5), and can't seem to find them anywhere. How do I go about finding them or requesting that they be posted?
You missed a bit on your explanation, like what format and such you were looking for... BUT (!)
These episodes/season 5 do not exist yet (have not been released) in any base format, like DVD. I looked at the upcoming release dates and the best I could come up with is 'maybe' Sept 09.
So, anything you may find on ANY transmission media (torrents OR usenet) will be live capture off television. Then the person doing it has to (hopefully) do the work involved in transforming it into (again) the format you are looking for (dvd, xvid, who know what).
It has been my experience that folks doing tv capture generally don't know what they're doing. I have over 10 years experience doing it, in both standard and now high definition. It takes good equipment, great original signal (hopefully a digital source), and lots of time and effort. The result is, that whether the material is posted on torrents or usenet, usually pretty dismal.
I'm assuming that since you already have some of the episodes, that the 'original source' was off-air (or satellite or cable) and went through some encoder card/box (known or unknown). Then s/w manipulation to cut out the commercials, spruce it up, etc.
There were lots of folks 'back in the day' doing that before DVD's got popular. Just about nobody doing it now. Except the 'thin edge of the wedge' folks dabbling in HiDef.
So, in a nutshell, you're best bet is to wait until it's released (on DVD), unless you find a source, are 'satisfied' with the picture/sound quality, and go from there. Of course, you could spend $xxxx (if you have access to a pristine signal) and do it yourself.
FYI, I have two machines, one about 5 years old I built around a a standard-def capture card (>$2500), and another I built about 8 months ago to do HiDef capture (about the same cost, but drives and capture card cost has dropped significantly in those 5 years!).
So... them's your options.
EXCEPT...!
I didn't stop to think that virtually all the networks now (particularly NBC) 'stream' their prime-time shows through the internet. If you have a decent connection, and can somehow figure out how to 'capture' the steam as it hits your PC/box, then you could take the bits and figure out how to process them for the format you want. An interesting thought. Maybe someone out there has already 'done the homework' (either have or it's a lot easier than I figure), I'll have to spend some time on it in the next few days and see what I can come up with (ramp up 'MR BIG' machine and take a wack at it).
It appears that the NBC site has all the episodes on it (Season 5), the trick will be in somehow storing and manipulating it.