Well, the most flexible distribution — by far — doesn't use any kind of packaging system, includes a lot of printed documentation (albeit not exhaustive), doesn't use a packaging system as far as I know and will certainly get you kudos. I refer, of course, to the GNU deluxe distribution package, costing $5,000US; see http://www.gnu.org/order/deluxe.html
If that's out of your price range, you might take a look at SuSE, which is very well documented from an end-user point of view. It has a package management system, but you can always ignore it (I think the DVD has source code in SRPM format? You can get the original tarball out with the rpm2cpio and cpio commands)
For general linux documentation, there's a whole ream of stuff on www.tldp.org,
including printed books that you can buy and/or download. I would strongly recommend trying to learn Linux internals from a book before breaking out the source code or manual pages, because it will explain the reasoning behind different design decisions and implemented standards, which manual pages (and often even the source code) doesn't.