Since you aren't really asking about the forum posts and the commonly available mails spread all over the internet, there was only one single pdf file "
pre-whitepaper draft" written by satoshi himself. Apart from the code files and the now available whitepaper, there was a pre-whitepaper prior to the one which is present now.
satoshi first appeared on the internet on August 22,2008 when he sent a mail to wei dai discussing about his e-cash pre-release draft. The pre-whitepaper draft was very much different from the one which is available now and significantly changes were made in the final version of the whitepaper and was published by satoshi in the cryptography mailing list. An abstract from the
ecash.pdf file
Title: Electronic Cash Without a Trusted Third Party
Abstract: A purely peer-to-peer version of electronic cash would allow online payments to be sent directly from one party to another without the burdens of going through a financial institution. Digital signatures offer part of the solution, but the main benefits are lost if a trusted party is still required to prevent double-spending. We propose a solution to the double-spending problem using a peer-to-peer network. The network timestamps transactions by hashing them into an ongoing chain of hash-based proof-of-work, forming a record that cannot be changed without redoing the proof-of-work. The longest chain not only serves as proof of the sequence of events witnessed, but proof that it came from the largest pool of CPU power. As long as honest nodes control the most CPU power on the network, they can generate the longest chain and outpace any attackers. The network itself requires minimal structure. Messages are broadcasted on a best effort basis, and nodes can leave and rejoin the network at will, accepting the longest proof-of-work chain as proof of what happened while they were gone.
The file was available for download at
http://www.upload.ae/file/6157/ecash-pdf.html once. But currently, it isn't available. We need to reach out an early adopter and check with them if this file is present still.
Similarly Hal was the one to share with us the early 2008 code. The code was very much different from the January Bitcoin 0.1 Code.
