I have studied lethal white foal in paints being as I own a paint mare, and have also encountered Lethal White Foal Syndrome. LWFS comes from the crossing of two overos, it is not exclusive to frame overos. Overo is a recessive gene, and when you cross two overos you run the risk of havig a foal with LWFS. It got the name Lethal White Foal because the foals are actually born with very little to no color, or white. They are born without the ability to digest, therefore they literally starve to death if not put down.
You can cross two tobianos, a tobiano and an overo, or an overo with a non-paint horse and you will be fine.