I was more thinking of a "MIRV on patrol" scheme. The warhead has small de-orbitation booster, a re-entry nose, and it detonates near the ground like a conventional MIRV. It's just that would be designed to remain several years in orbit, undetected, before the strike order. The "undetected" part is difficult, especially if you have a hundred. There is basically no background noise in space at that depth of field, so a radar return is unmistakable (the doppler and delay allow a ground radar to filter anything that comes from within the atmosphere, or GEO satellites. then the "ordinary" LEO are all mapped in public databases for the security of civilian missions, anything extra has to be military or alien). The warhead would have to be coated with B2-like radar-absorbent material - which has never been tested in space for any kind of extended duration, to my knowledge. Then you need some dish for communications (which makes for a fine radar mirror), and some power source (if not solar panels, then a RTG but then you give off heat). Eventually, some way of arranging the unnoticed disposal of the warhead on the ground after a decade (the orbit will decay, and you don't want it to fall on a random location).

So I think the case for the enforcement of the space demilitarization treaties is quite clear: nobody can build this up today and remain unnoticed for too long.

Pierre