Heli outfits in the lower 48 are limited at best. Helitrax
operates out of Telluride Colorado. You have the Wasatch Powderbird
operation out of the Cottonwoods in Utah. There is also the Ruby Mountain
Heliskiing out of Elko Nevada. I am pretty sure there is an outfit or two out of the Washington-Idaho states.
Wasatch Powderbirds are nice and close to a lot of resort in Salt Lake. The thing is you'll be riding the same mountains I have accessed and 100's of people do by hiking in. It's the same terrain that earn your turns backcountry users get. If I am going to drop money on a heli trip, I want it to take me to terrain that isn't easily accessed by hiking, skinning, or snowmobiles. The locals take great pride in nabbing the terrain they like to take their clients too. You will definitely not get prime untracked.
Helitrax operates out of the San Juans and that terrain is remote enough. Maybe some bilers getting back there, but probably not so much. The snowpack is a different thing. I would hazard a guess that most "Oh my god" terrain is not safe to ride most of the time. The continental snowpack here is the most avalanche prone in North America. Even a heli outfit has to be conservative. Telluride ski area is one of the few I haven't visited in the state, but it looks amazing.
The Ruby mountain guides are out of Elko Nevada. One of the oldest and most succesful heli operators in the states. Looks like fantastic terrain and they do all inclusive packages. No other resorts nearby. Something like 6-8 hours to Tahoe, 4-5 to Salt Lake City.
Alaska or BC Canada have outfits that get you to much bigger terrain.
Also if it's untracked you are looking for, why not look at snowcat access too? Snowcats are not grounded in bad weather and get you about the same vert for a about half the cost.