Motorola just kicked off a new Test Drive program which is basically an advanced soak test platform. It will be basically give folks earlier access to updates for a longer time than than the normal soak test. This new Test Drive will typically last several weeks to a month instead of the typical 2-3 days for a regular soak test.
Moto kicked off this new program with Android KitKat on their Droid RAZR M from last year. Here's a quote with a few more details,
The Test Drive program is a pretty exclusive club as well. You may not get in just because you want to. Motorola is apparently recruiting only those who have been active in the Motorola Feedback Network, and those who have proven that they will offer quality feedback during testing. Motorola is specifically trying to avoid testers who just want to play with early software and not give back at all. The program is supposed to be completely confidential, but of course an invitation email has already leaked.
The email says that if the test software bricks your phone, Motorola will send out a replacement as soon as possible, which is nice. The first device on track for the new Test Drive program looks to be the DROID RAZR M. The email doesn't mention what the software to be tested would be, but the leaker claims it is a test for the Android 4.4.2 update. If that's true, RAZR M users may be seeing some KitKat action around Easter time.
It is unsurprising that it is not a foregone conclusion for anyone to get into this Test Drive program. The requirements to qualify are a bit more stringent than your average soak test, but that's to be expected due to its exclusivity.
Source: PhoneArena & MotorolaFeedbackNetwork