It would be very useful if it was possible to create a sequence with overlapping source clips. Or to be able to do that with stacks. There are some workarounds for this but the issue is that most of our shots start at 1001. There isn't a way to offset a whole source globally in a stack, so the sources are just layered on top of one another.
For that case it was suggested to make two sequences and stack them. Within those sequences I would need to construct the appropriate timing where the "empty space" is filled with transparent movieprocs. Though not impossible, that's a lot of steps and quite complicated to program. Which is essentially what we are looking to do - programatically generate a sequence with overlapping source clips.