You may very well be running a custom ROM based on the Android 2.3 (Gingerbread) leak on your HTC EVO 4G right now, but guess what. According to Sprint, new phones come with the official Gingerbread build right out of the box.
The black device is listed as out of stock at the moment, but the white one is available for anyone who wants to buy a "new" phone that's almost a year old and whose identically priced successor could be released as early as next week.
For everyone who's already months deep into their ownership of the EVO 4G, it looks like an OTA software update notification should be appearing in your status/task bar very soon.
How "finished" last month's leaked build (version 4.12.651.1) was compared to whatever will be riding the airwaves soon and is currently shipping on new phones is unknown, but it's probably best not to expect to see a new version of Sense. Perhaps a trip to my local Sprint store is in order today, if only to ask about the new software.
Update: Oh well. Sprint has confirmed to Engadget that this was an error. The EVO still ships with Froyo and will be updated to Gingerbread as soon as the carrier can do it.[Sprint] Thanks to everyone who sent this in!