There are a few proof Ike Dollars struck on clad dime planchets known. These are very rare and highly prized by Ike Dollar collectors and mint error collectors. This off metal shows Eisenhower's head positioned nicely on the obverse and the eagle on the reverse. This Ike Dollar on a Dime mates to another Ike Dollar off metal since it has a straight edge from being struck next to another planchet.
Proof coins are struck by technicians who hand feed the blanks into special presses. They are produced, examined and packaged using extreme quality control. It is very unusual to find major proof errors. A few broadstrikes, off-centers, double strikes (in collar) and off-metals have been known to be found in sealed proof sets. Proof errors are aggressively sought after by many error collectors.
A very small group of Proof errors recently came from a collection that was auctioned by the State of California. The U.S. Secret Service inspected and released this collection to the State of California determining that it was legal to own. The State of California then auctioned the collection and it has been dispersed since the sale.
Proof Errors are featured in chapter 21 of the
NLG award winning book, World's Greatest Mint Errors.