mismatched non seqeuntial turbo?

I suppose if your a large German car manufacturer (which I'm pretty far from) but what would be the pitfalls and issues associated with doing this on a small block on a budget? Any ideas? What kind of offset would work the best? Would you want the biggest and smallest? one slightly bigger? two the same with different turbine wheels? Anyone interested in a no lag, constant boost a-body or is it just me?