You can easilly lure players in Beta if rewards there are valuable enough to outweight the risk of open PvP. Right now you make more profit by staying in Alpha, why would you go to beta if you're not a PvP fan ? 

The mining outposts are an interesting idea. One may also take example of DAOC, where PvP was the high-end of the game with ranking and special bonuses and abilities. The keeps were really fun to attack/defend with their guards and siege warfare. And don't forget the relics which allied people and influenced the whole world through bonuses and relic-related areas.