EDIT: Never mind - you actually mentioned this.
A lot of this is over my head... but it is my understanding that at a certain point you are comparing queries that are slightly restructured versions of each other in order to prompt the QO to use different kinds of joins. Can you not do that same thing by explicitly stating which join to use with join "hints"?
FROM PRODUCTION.[PRODUCT] AS [p]
INNER [ HASH | LOOP | MERGE ] JOIN SALES.[SALESORDERDETAIL] AS [d]
ON [d].[PRODUCTID] = [p].[PRODUCTID]
AND [d].[MODIFIEDDATE] BETWEEN '20111201' AND '20111228';
Thanks for the information.