You can accomplish Aliasing listings via the regularly known method of using Pathauto and Entity API's "Entity Tokens" along with the latest version of drealty 3.x.

Once Drupal RETS Real Estate Framework (aka Drealty), Entity Tokens and pathauto are enabled, you will see the Drealty entity tokens listed under "patterns".

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OLD METHOD:

Aliasing listings and giving them pretty URLs like real-estate/single-family/arlington/virginia/584837 requires two modules:

One important thing to note, if you are using Media module with File Entity, you need to see this issue first: #1540010: pathauto_entity_entity_insert causes file uploads to fail with File Entity

Setting up Pathauto

With Pathauto, Pathauto Entity, and Drealty installed, head over to the URL Alias configuration settings in your Drupal admin. Edit your URL Alias 'Patterns' settings, and you should see Drealty Listing in the list. You can choose from any number of tokens available if you have added Fields and setup your property types for importing listings.

Now that the settings are in place, the next time listings are saved or imported, they will receive proper URL aliases.

You can also use these in code to link listings with the l() function like so: 

print l('View this Listing', 'drealty_listing/' . $entity->id);

Which will print its URL alias.