1955 Latour, 1967 Lafite-Rothschild

[wondersofwine]

British sources might be your best bet. Michael Broadbent has done tasting notes about Bordeaux that go back decades. You might contact the British firm of Berry Bros. and Rudd to see if they could be of help. On this board Winoweenie might have some information for you but those vintages are from long before I began collecting and out of my price range as well. Here's a link to the Berry Bros. and Rudd historical vintage chart: http://www.bbr.com/US/shopping/vintage-chart.lml?ID=65P2BGX3PN100B7
You can copy and paste that url in your address line and then should be able to link.
If I read it correctly both vintages you mention should be showing their age now but the '55 vintage was a much better vintage than '67 on average. (Of course with first growth Bordeaux the producer may exceed the average for a vintage.)