The real shame is that ancient lead isn't the only alternative, just the cheapest. Lead could be spun in centrifuges and then securely cast to remove such contaminants. This has been done with silicon, in that case to remove unwanted isotopes. It is a wildly expensive process but at least it is a process that could produce an infinite amount of product, rather than ancient lead of finite supply.
But what compound? PbH4 isn't stable. PbF4 is barely stable. Maybe Pb(CH4)4 ??? Naively, I guess that you'd get even better mass resolution. Molectual mass of UF6 being ~352, vs ~267 for Pb(CH4)4. Good use for all those leftover centrifuges ;)
You're getting downvoted because you're nitpicking vocabulary. Most people understood "infinite amount of product" to mean "functionally infinite, given the low demand and large supply."
