There are things that would extend those chains, but the element of the second SC wouldn't match the first.
Yeah, there's a few multi-element combos for Marksmanship:
- Induration > Last Stand = Fragmentation,
- Scission/Impaction > Hot Shot = Liquefaction,
- Impaction/Compression/Scission > Slug Shot = Detonation,
- Tranfixion/Scission > Last Stand = Reverberation,
- Compression > Leaden Salute = Tranfixion.
You could pull it off, but how many situations would you be in where something is weak to multiple elements, and your mages are aware enough to change elements on the fly during MBs?
Distortion > Leaden/Wildfire > Wildfire is about as good as it gets for us.