Elinchrom Quadra Lithium Ion Battery Issue

I had a look at the spec of the lead acid. They're 12V 3.6Ah.

I wonder if there are any lithium ions of the same spec that could be made to work with it or if there's a market for someone to build some extra circuitry that could be put on the Elinchrom lithium ion batteries to fix the voltage issue. That way someone with lots of 1st generation heads would only need to pay once for the voltage converter and not have to get their flash heads modified at all.