if you google "convert Lincoln vacuum headlights to electric" there are some videos and a bunch of the top results point to the same eBay seller. People with other hideaway headlights seem to get directed to try adapting the available Lincoln kits as oddball Mercuries and such don't have as much support apparently.
I spent a little bit of time reading about it, and a few people at least suggest really going over the vacuum system (i.e., change all lines) first as that is relatively cheap to do and might fix it good enough to make you happy.
I can understand wanting to be free of vacuum however.
Good luck either way!
I have a friend that made his own kit for less than $100, but he was very good with electrics and sourcing the right parts to make it happen. These guys make a kit for Mark IIIs: https://catheadlights.square.site/product/69-71-lincoln-mark-iii-electric-headlight-conversion-used-...
So yes, it can be done...and you don't have to spend a lot of money doing it, provided you are good with sourcing electric motors online.