I am also looking for more solutions to this problem.
This is what I have come up with so far:
-As szhang said, your top priority should be to continue to build ongoing quality links to the homepage. I've noticed an increase in rankings across the board from doing this, pages with 0 backlinks rising in the SERPs after quality backlinks added linking only to homepage. It helps here if your homepage/main keyword you are targeting is a related broad term for your pages/secondary keywords. So for example if your main kw is Digital Cameras and then all your URLs are models of digital cameras, etc. However I am sure this method is still effective even if they are not related.
-If you own the site, try get into the mindset of being an affiliate for yourself. Pretend your site is now a small Amazon, and you want to create some sites to promote it. A site with many pages should have multiple categories to create a nice hierarchy. So using the previous example again, lets say your site is selling Digital Cameras and this is the main keyword you are targeting for the homepage. Then you have categories like SLR, Point and Shoot, Underwater, etc. Then all your pages are various products from each category (doesn't matter if they overlap) e.g. Kodak 2100X SLR.
Setup free web properties for each of these categories, and then create a page for each page on your money site in that category. If your money site is up and running already, this can be easily outsourced as everything is done you just need to create some accounts and make the content unique.
Then blast the hell out of these sites with automated tools
Rinse and repeat for additional keyword/anchor text variations.