Don't know if he's too old now at 33, but how about someone like Geremi? The ex Real/Chelsea/Newcastle player? I think he's kicking around in the Turkish league and would probably be available for a modest fee, not sure about wages. Strong, powerful, versatile and experience of the top level of football. Happily plays centre mid, right back or centre back. Would surely be a great presence in the dressing room for the youngsters.
Robeson from boro is going to play abroad so that's a no but trotter from millwall looked a menace so yeah maybe ? If he played like he did against us every week.