What is the name of the now common practice (mostly in commercial branding) of forming A Word containing Two Capital Letters e.g. SureStart, WordPad, ShopTalk etc.?
The practice you mention is described thus in the article on capitals in The New Fowler's Modern English Usage by R.W. Burchfield (Oxford University Press 1998):
The practice you mention is described as Medial Capitals. Worth noting is the newish mostly commercial habit of inserting a Medial Capital letter into the name of a product, a process, etc.: e.g. CinemaScope, InterLink.