I've had the same experience on a 2 litre 900 HPT. No sign of a problem until I parked the car up one morning and then tried to restart it a couple hours later....nothing. The giveaway is a strong smell of electrical insulation buring when you lift the bonnet.
The RAC carry spare SAAB DI packs in most areas because it's a common failure mode, but rarely have both the red & the black available.
If the problem is not common in the US then different suppliers may hold the answer.