You could do it with totals and run lines. A half a run teaser could work like this:
-1.5 favorites would be moved down to -1 and +1.5 dogs could be moved up to +2.
I think 1.5 run teasers could be offered for totals.
Payouts could be determined by the odds because it's obviously different from basketball and football where you almost always have -110 lines.
I think these teasers would help encourage betting and isn't that what the books want to do most? I think this could be hugely popular, has it ever been tried? Why doesn't it currently exist?