I wrote a virtual terminal subsystem a while ago. I gave it keyboard layouts with the ISO 9995-3 common secondary group. No daggers, alas. But ISO 9995-3 does have pretty much all of the combining diacritical marks. <Group2> <Level3>+D05 is combining diaeresis. In practice I find myself not appreciating that as much as I appreciate being able to type U+00A7 as <Group2> <Level2>+C02.