There are "short skis" that can be used with regular hiking boots. I researched those as an alternative for approaching ice climbs. However, there is some major issues with these
They are not really suited for soft winter snow as they are simply too small and will sink in deep. They are more suited for compact (early) summer snow
Hiking boots are ...
While adapters exist, I have not seen any in use for obvious reasons:
Alpine skis and boots are heavy and there is not much fun in carrying those up the mountain. I already have a rather heavy touring setup (for todays standards ;) ) but my alpine setup is way heavier
Touring boots give you a lot of flexibility in walk mode (typically around 60 degrees). ...
They do exist. Whether they are the right solution is a different discussion.
Daymakers AT Adapter
There is a review about them here.
I personally have never used them myself so I can't speak to their quality/use. I just know they exist.
Manziel makes an important point though about the cost/benefit of the adapter vs a used setup.