Wireless local loop phones. Cell phones that look and act like a desktop landline phone. They even did a version that had POTS jacks instead of a handset, you could pull the plug on your demarc and plug into it instead. This was the great idea for spreading telephone connectivity in the underdeveloped world. (Most notably India, but what was then US West was hot to deploy it in the more desolate parts of the US north and northwest.)
But it didn't really go anywhere, wasn't enough money in it I guess.
But that's still a neat hack.