for(var i = 0; i < balance.toNumber(); i++) {
  myERC721Token.tokenOfOwnerByIndex.call(web3.eth.accounts[0], i)
  .then((id) => { ... });
}

import "openzeppelin-solidity/contracts/token/ERC721/ERC721Token.sol";

contract MyERC721Token is ERC721Token {

  function createNewToken(...) {
    _mint(msg.sender, index);
  }
}