50 players have scored over 1000 runs batting 4-7 with an average of 35 and over.
3 average 50+ (Bevan, Sarwan, Hussey)
6 more average 45+ (Pietersen, Crowe, Boon, Dhoni, AB de Villiers, Kallis)
Overall in ODI's this middle order position averages 28.81 (probably dragged down by number 7 but ah well)
58 players average over 35 with at least 1000 runs in the top 3. Most interestingly Dhoni has 1019 @ 78.38
3 players average 50+ (Dhoni, Richards, Yousuf)
7 players average 45+ (Turner, Tendulkar, Lara, Abbas, Greenidge, Dippenaar, Kallis)
This position averages 32.35 overall.
Not outs are a pretty huge factor here.
1-3 overall: 1003 NO
4-7 overall: 3702 NO