Putting aside demo, and acetates that could command hundreds of thousands even millions.
What standard issues of Beatles records are the rarest to get hold of. My guess are the Butchers discs. Any others?.
Rarest and most expensive are not always one and the same, I am in the process of collecting all the Parlophone albums both mono and stereo that came with the black and gold label, and although only 900 of the Beatles 'Please please me' on that label were supposed to have been pressed before the label changed to the familiar 60's label with the yellow Parlophone, there is hardly a week goes by when there not one on ebay. There are some extremely rare albums on that label much rarer than the Beatles. Back to the Beatles then, I would say the UK pressed export albums are much rarer than 'Please Please Me' stereo black and gold but do not attain the price of PPM. You can read all about them here. www.yokono.co.uk/collection/beatles/uk/guide_lp_export.html