There are other considerations. On the high flange hubs, the spoke holes are spaced much farther apart. This means you face less risk of hub failure with radial spoking (because two adjacent spokes aren't as close together and pulling on the same part of the hub). Also, with large flange hubs, you have the option of using 4-cross lacing (and various exotic lacing patterns if you're so inclined) -- with low flange hubs spokes will cross over the heads of adjacent spokes and create a number of problems. Plus, high flange hubs are produced by metal spinning, which leads to a much higher metallurgical quality than you get with low flange hubs, which are simply machined. And while it's a point some folks like to debate, I find that both rotational stiffness and lateral stiffness are greater with high flange hubs (which is the primary reason why most track riders still use high-flange hubs). So I'd try to stick with the high flange hubs.
Dura Ace high flange 7600 hubs were rapidly disappearing and prices were skyrocketing several months ago (in one year, hubs jumped from about $140 to $330-350). Then Euro Asia Imports placed a large order in limited sizes and configurations that encouraged Shimano to do one more run. They're a pain to make and require specialized hand machining skills, so Shimano wasn't all that excited about it. They also anticipate that with the impending acceptance of disc wheels in keirin, the market for traditional hubs will drop. EAI pushed a bunch of these hubs into the market, and prices dropped hard as everyone bought volumes of them and then wanted to sell them in turn. Now they're running out so prices are going right back up again. I wouldn't count on another production run, and as far as I know only single-sided hubs were produced and only in some limited drillings. So it's worth it to hunt down some 7600 high flange hubs if you're interested. I bought a couple extra pairs before they hit their peak prices -- if you can't find a pair elsewhere, PM me.