HeinOnline's American Law Institute Library has the most comprehensive collection of drafts for the Restatements of the Law.
Restatement, Second, Contracts (1962-present)
Restatement of the Law, Contracts (1924-present)
Jenkins has select drafts in print and on micro in the library. Search the Jenkins' catalog for Restatement* Draft* Contract* for a full list of available drafts.