Millenicom does not have any Sprint LTE devices. In fact Sprint themselves only has the Sierra Wireless Tri-Fi Hotspot for their LTE network - no USB modems.
sure, if there were any. There are none. It's becoming more clear to me that the Telco's want you to buy a Smartphone and a tethering package. They will continue to offer a hotspot device but USB sticks are rapidly being phased out.