Like this:
http://youtu.be/xrtfH_VgGZ0?????
Formal Tai Chi...? not in the most literal and strict sense perhaps, but I think it is in the broad sense.
As for it being internal, I would say absolutely.
I will admit that the video I posted contains something I consider a fake sword, (during the form demos) but real swordsmanship. The way the sword flexes and moves suggests it is historically inaccurate as a Chinese sword. A sword should not bend like that in such motions, it is too flimsy to be used in battle, but is fine for showing off moves. Such a sword is also too light to be accurate in a historical sense and is largely a modern Wushu style sword, not true to the old forms. However they do depict much better swords later in the video, so it isn't a big deal, I am just sharing my opinion that you should practice with a sword with real weight and sturdiness.