It's a good question.
I wish I had as good an answer.
A lot of SEO's would say that you would get most leverage out of MSN for this type of strategy, followed by Yahoo and Google.
On the basis of (the little) I know about Google I'd say:
- If the other site is an authority site, and
- If the other site has significantly more than 50 pages, and
- If the other site links out naturally to a large number of other sites (not low quality sites), and
- If your link appears in an "editorial position" as opposed to a sidebar or footer position, and
- If your site has very much more than 50 pages, and
- If each of the links on the other site leads to a separate page on your site,
then each of your pages will benefit reasonably well from the separate links.
Your other suggestion of using the same anchor text on 50 pages on another site leading to a page on your site is more likely to be spotted as a "sitewide" or "paid for" link and devalued. From what I've seen, though, some sitewides still work well with Google.