Andrew,
Something like this can happen if you have an extremely large timeline. Try checking your combination of "scale" and "days" values. I'd try to keep the timeline length (the number of cells in the last time header row) under 1000.
For comparison, the main Scheduler demo initializes in about 140 ms in Chrome (14 resources, 12 events, 365 timeline cells). Increasing the number of resources and events doesn't have a significant impact on performance (the rows and events are rendered progressively during scrolling by default) but the timeline is rendered in full during initialization.
Let me know if it didn't help.