Like some of you, I use two Google accounts - my personal one, and a work Google Apps account. Recently I have been getting a bit frustrated with only being able to sync one Google account via the Google Drive app for Mac.
After a bit of playing about, I managed to do the below to get two accounts to sync:
1) Create a new user on your Mac
2) Switch user to your new account
3) Set up Google Drive on your other Google Account
4) Share your new Google Drive folder with your main Account (Make sure it's Read/Write!)
5) Switch back to your main account
6) Add a shortcut
As long as you're logged into both users on your Mac, it'll continue to sync in the background.