This one is 15.000 on ebay!
Referring to the earlier points made in this thread, I continue to be amazed that photos/postcards signed on the back make such a premium over signed album pages. As Tiziano said they are basically the same - unless of course they are linked to a specific event like a flight or filming on loaction somewhere.
I fear I may have said this before but for me the same applies to signed photos and records. I realise that they are much better to display and much rarer than signed album pages but the signatures alone are the same whatever they are on - in fact on the backs of LPs with tons of text and scuff marks the signatures can be quite hard to make out. Obviously if there are only 100 or so signed LPs around they should have a big premium but to me they shouldn't be 20x the price of a nicely signed album page.
With some tasteful framing (for instance matted under a vintage LP or photograph) a signed album page can also make a cracking display.
As for future prices, it is hard to believe that the Beatles prices will go down but you never know. Silent film stars are also not fetching the prices they used to. Anyway, I have a feeling we'll all be long gone before that happens.