Sorry for the slow reply, Corey :)
In previous versions of JBossAS, there was an exposed JMX server with an option to mark a folder as one that the deployment scanner should look at. This option still exists in AS7, but, we haven't integrated with the management ability yet. THis means we can't do it on the fly, currently, in the current toolset is a bit hurt by this missing feature.
It is still possible in the raw configuration of the server, howerver. THis means you can mark your server directly to scan some external folder by modifying your configuration and adding a deployment scanner. The instructions for it are over here: https://community.jboss.org/wiki/DeployingAnApplicationFromAnExternalDeploymentLocation
To make use of this, double-click your jboss-7 server inside eclipse to open the server editor. You can then switch over to the second page, "Deployments", where you can change the deployment method to "custom" and set any folder that's on the same filesystem as your eclipse installation. Once this is done, you can add that folder to your server's deployment scanner lists as per the wiki above.
Hope this helps!