In the RIPE region, being multihomed or planning to be it is not a sufficient condition for getting a PI prefix. And even if it was, the hit on DFZ is the same as from getting allocation from LIR. Even if they get their own /32, the hit would be the same (modulo individual FIB/RIB implementations). Consequently, there's work in progress to modernize RIPE IPv6 address policy. http://ripe62.ripe.net/presentations/148-wg.pdf p. 19 and forward.
Cheers, Martin
Martin, Possibly the hit might be the same, but possibly not. An organization that requires a second /48 from their upstream might get one that can't be aggregated with the previous one. It is my understanding that ARIN is attempting to structure their assignments so that if such growth occurs in PI space, it is likely (though not guaranteed) that the network will get a subsequent allocation that can be aggregated with the first. George