Earlier quoted context omitted.
You can edit the Info.plist file (you probably already know this!) to get the IDE to launch under JDK 7 in OS X. A recent EAP release actually had a bundled JDK 1.7 for OS X, although it seems the final version's download doesn't have it
this doesn't actually work. editing the plist doesn't do anything on IntelliJ 13 mac.
Are you sure? I just installed the community edition of IntelliJ 13 and changed the JVMVersion to 1.7* and IntelliJ is definitely running under the Oracle 1.7 JDK