Actually, the most visible A-rated TNO corporation is AET, which stands for Armaments Eireann-Tir. AET, like essentially every other weapon maker in shadowrun, makes nearly every type of weapon which can be found in the book; AET models tend to be a touch heavier and a touch bulkier. In the TNO book, the Wonder Twins Carl Sargent and Mark Gascoigne also introduce the counter to the 'ultra-armor' they devised for us and put into the hands of the elven Welsh Duchess Rhiannon Glendower in the London Sourcebook, to wit 'morph-seeking weapons', which are basically a GM's 'blue bolts from the sky', weapons which pretty basically guarantee a kill-shot each time, every time.
Lesson you should take away from the London and Tir na nOg sourcebooks? Sargent + Gascoigne = Suck.