You can mod the Karakorum
System to a DIY split. It is pretty damn nice from what I've seen, though it has it's drawbacks like everything. One of the major sticking points is price. For $600 you do get the system and bindings.
As far as ripping your board in two. Everyone I have known that has done it has said it's pretty easy. Just like you said. It's just a fair amount of time and effort. The inside edge is nice, but it's definitely not necessary. I'd say go for it.