Tomari-te in known to be very similar in technique to shuri-te, with minor differences. It is described as being very soft and fast, emphasizing lower stances than shuri-te.
Who know's if there is a "pure" tomari-te still being taught, but there are people from authentic tomari-te lineage.
One lineage is of Matsumora Kosaku, passed on to Seiyu Nakasone and others. The other is of Oyadomari Kokan, passed on to Seikichi Hokama (not sure if these men are still living). I don't believe either Matsumora or Oyadomari type tomari-te are commercially taught, at least not widely; rather as a part of normal Itosu Karatedo.
Although Motobu Choki really practiced his own "style" based on a combination of his various instructors teachings, he did learn tomari-te from Matsumora. So Motobu Ryu as taught by Chosei Motobu can be thought to be very influenced by tomari-te.
Most Okinawan ryu-ha of shorin lineage have tomari-te in them, as the kata Seisan, Wanshu, Rohai, Wankan, Wando, Jion, and others are from tomari.
I hope that helps!