I just put a few of the URLs that were already on the page(s) into linkscape and saw what came back, then did a full report once I found one that was pretty much ONLY using that link to rank.
The link I picked was a deep link (not homepage) and only had this link going to it (according to linkscape), checking out the site the domain wasn't hugely powerful with only a dozen unique domains pointing in (none as impressive), but the page linked to had PR 4.
So, while it's a bit of supposition, I would imagine that the link is accounting for most of the 'juice' passing to the page (and indeed the site).

The 100 link limit suggestion was removed a while ago, though it's is indeed best not to go wild with it.
