Finding stored procedures with missing indexes
Having not thought a whole lot about this, and answering just the specific question asked, here is a way to identify all the stored procedures that reference tables that have at some point been identified as candidates for additional indexes. Unfortunately this is a very loose relationship ... I don't believe there is any straightforward way to say "this stored procedure queried this table and could have used this suggested index" unless you started parsing the sql text and fuzzy matching against the columns etc. recommended by the missing index DMVs. This is a start toward that process. That said, I kind of agree with Henry, there are plenty of more direct ways to analyze and address performance problems in stored procedures you have identified. Examining the execution plan, for example, should provide some clues much more intuitively than this round-about method you want to pursue. In any case, here is a query to start you off:

SELECT 
  [Procedure] = QUOTENAME(OBJECT_SCHEMA_NAME(s.[object_id])) 
        + '.' + QUOTENAME(OBJECT_NAME(s.[object_id])), 
  [Table]     = QUOTENAME(r.referenced_schema_name) 
        + '.' + QUOTENAME(r.referenced_entity_name),
  i.equality_columns, 
  i.inequality_columns,
  i.included_columns,
  s.execution_count,
  avg_time = s.total_elapsed_time*1.0/s.execution_count
FROM sys.dm_exec_procedure_stats AS s
CROSS APPLY sys.dm_sql_referenced_entities
(
  QUOTENAME(OBJECT_SCHEMA_NAME(s.[object_id]))
  + '.' + QUOTENAME(OBJECT_NAME(s.[object_id])), 'OBJECT'
) AS r
INNER JOIN sys.dm_db_missing_index_details AS i
ON i.[object_id] = r.referenced_id
WHERE r.referenced_minor_id = 0;


Note: the DMVs usually only have data since the last restart.