I don't think it really is possible in the way you are suggesting it. I don't think the Red Wings drafted Lidstrom thinking he would ever be as good as he was. If they thought this, they would have used their first pick on him. Players like Lidstrom, or Tim Thomas, are very rare and extremely unpredictable. It is far more likely the top players were top players that developed as such. In fact, everything Jim Benning stated regarding Olli Juolevi after drafting him suggested that he was very close to being an NHL player.
If you are drafting within the top five, you dam well better get a player that is not only close to the NHL, but has a very high potential. Just look at Pettersson and Virtanen. One was a pretty poor pick, the other a great pick. But they were both close to the NHL when drafted. Look at Scott Glennie. A terrible pick that wasn't close to the NHL when drafted.
The problem with your theory is that it relies on hindsight to prove that the player farther from making the NHL has higher upside. This is because a player's upside is judged based on his development curve, which depends on his current ability. Therefore, if one player has a very high ability at the time of being drafted, and another player has a lower ability at the time of being draft, it is counterintuitive to suggest the latter player has a higher upside, and in this scenario, the former player obviously is closer to the NHL. Sure, in hindsight, and after years of development, the latter player may turn out to be the better player, but at the time of the draft, it would be impossible to determine that.
