Frankly, I don't see any way to justify any literal interpretation of Versetile Expertise that -doesn't- let you pick "any weapon you're proficient in" as an implement. The implement group is "weapons you're proficient in", so that's what's there.
That said, it's pretty clear from the character builder what the intended interpretation is. Since the monk and versetile expertise were implemented, the builder has allowed you to take all weapon groups under versitile expertise as implements (as well as letting you take them as implement groups). Thus, one can divine (since this could hardly be unintentional) that since all weapons may be be implements, in games where the monks exist, all weapon groups area also considered individually as weapon groups. So while Versetile expertise lets you take any weapon group and any implement group, since all weapon groups are also implement groups, you may take two weapon groups, or a weapon group and an implement group.
That said, it's pretty clear from the character builder what the intended interpretation is. Since the monk and versetile expertise were implemented, the builder has allowed you to take all weapon groups under versitile expertise as implements (as well as letting you take them as implement groups). Thus, one can divine (since this could hardly be unintentional) that since all weapons may be be implements, in games where the monks exist, all weapon groups area also considered individually as weapon groups. So while Versetile expertise lets you take any weapon group and any implement group, since all weapon groups are also implement groups, you may take two weapon groups, or a weapon group and an implement group.