to me and says 'I want to go multihomed with you as a second provider, currently I have 8 class C's but they are all spread about the place'. Me 'You need to renumber then esp. as your class C's are within your current providers aggregate announcments (even though they are old, and thus technically PI' (there, that's me doing my bit for aggregation). Them: 'OK, give us a /21 to renumber into, you are a local-IR and we aren't'. Currently I have 2 choices as far as I can make out, give them a bit of my /19, break up my nice aggregate and ensure loads of extra announcements (and that probably none of them get routed by anyone applying prefix based filtering), or give them a new /19 all of their own (you've said it, that's the minimum size allocation) which actually solves their problem and mine, but this isn't an option currently available because currently it's one window per local-IR. So they have to go and become a local IR.
No they don't. You can ask the RIPE NCC for special PI space to assign to this customer. It seems they have a "chemical waste dump" to satisfy this kind of requests from.