LLC's have almost unlimited flexibility in structure. They can be managed by their members (owners), though I don't recommend that unless the members adopt a set of rules for how decisions will be made. Most of the LLC statutes provide for the possibility of having managers without providing any specific information about how managers will function. In contrast, most corporate statutes provide clear guidance on the role of directors and the authority and responsibilities which directors will have. I usually import some structure from the corporate model and specify that the LLC will be managed by a board of managers which will have the same rights, authority and responsibility that directors would have under the corporate statute in the jurisidiction where the LLC is being formed. Like in corporations, where the shareholders elect the directors, I provide for the members of the LLC to elect the board of managers and to set the number of managers. I have the board of managers function like a board of directors and engage the executive officers who will have responsibility for the day to day operations of the company.
Most LLC and corporate statutes do not require an ownership interest for serving as a manager or director. However, the members might want to require that.
Generally, when I form LLCs, I provide for an odd number of managers and for each manager to have a single vote. In privately owned LLCs (most of them), as in privately owned corporations, the members, managers and the executive officers are the same people. When a company (whether an LLC or a corporation) is obtaining investment capital from VCs, they generally want a right to appoint/elect at least one manager or director. If an LLC or corporation is held 75% by one individual with the balance spread in much smaller percentages among a number of other individuals, the majority owner may want (or insist upon) the right to elect a majority of the managers or directors.
I think in an LLC one could provide for some form of proportional voting if it was desired.
I think having a requirement that the board (of directors or managers) have members from more than one country might make sense where the company has operations and owners in in certain countries.