I think it might be difficult to select parts/components with 120VAC running across it, but if I can transform it down to 12 VAC that should be much easier to deal with.
Such transformers have been made and sold for many many decades and are usually called filament transformers as they were commonly used to power the 6.3 or 12.6VAC filament for common vacuum tubes. They came in many physical sizes depending on the output current rating for the transformers and small 100-200 ma ones did exist.
This radio shack one might be useful:
Lefty