I really wanted to implement omeka as a resource within the durpal-based Leonardo Education Forum site in order to keep our somewhat skittish users in one place and so that discussion forums could concentrate on the exhibits without having to go elsewhere.
Luckily I found a hack until there's an api :) that allows seamless integration.
Basically you start by creating a page that you want to embed your omeka pages into and name it something like 'exhibits'.
Then you can create a block with the code to embed.
I used an iframe:
You can also use some php code:
$output = ob_get_contents();
...but it overrides drupal's style sheet so the effect is not-so-good.
Once the block is saved, configure it to show only on the page you made as 'content'.
Voila! That should be it.
see here: http://artsci.ucla.edu/LEF/exhibits
You could embed the code directly into the first page you made, but it sent me away from the site to the link. I'm aiming to mask the omeka host with the drupal site.
**note this is only tested in firefox on macOSX