We know that some users prefer to roll there own, and the good thing is, SmartThing's platform encourages just that. In light of this, we've created a repository of SmartApp code that contains multiple versions of the SmartApp, including official versions that buffer and don't buffer events as well as DIY versions that don't include the official OAuth integration.
Keep in mind though, that a DIY version is not an officially supported version, it is a DIY version because of it's nature and because it can potentially be high bandwidth based on the number of devices and events you have (as it's sending an event to Initial State immediately as the event is processed by SmartThings).
There is a GitHub repo with all of the code of both SmartApps and the instructions for how to install them in the readme. Keep in mind that the DIY version will not show up in your account page under the Streaming Integrations like the current official version does.