For what its worth I do not recommend the Ground Shark. Although the durability and concept is excellent, to me the design needs work. I do not like the small sized shovel/scoop end because it requires multiple pentrations into the soil to get a decent size hole, especially for deep targets to avoid damaging finds. Don't get me wrong, I'm not wanting to dig a crater and make my digging obvious to landowners and others, but if they would come out with a wider scooped end resulting in less perimeter penetrations to get the soil out to check the find, I would buy it as soon as available because it does excellent in hard ground or areas with lots of roots.
I've actually quit using my Ground Shark and started using a mason's hammer with a pick-style end. I carry it in a leather holder on my utility belt, along with a surplus bayonet for probing around the hole, its light-weight, and allows you to always keep one hand free to switchover to if the other hand gets tired from swinging the machine.
If they asked me I would tell Lesche to make the scoop twice the width it currently is. If they do make one in this fashion I'm not aware of it.
If you can find one, the Penetrator is a real good from what I've heard is a good durable digging tool, but I don't think its still in production but know there are sites that still offer it. Do a google search if interested.