Of the nearly 16,000 instrument approach procedures in the U.S., over half are RNAV approaches. Of those, 1884 have LPV minimums. About half of the LPV approaches have been created for non-Part 139 airports (no large air carrier service), so GA aircraft are getting a good deal.
The process can take a few years, but it’s public at the FAA’s Instrument Flight Procedures Coordination web site (https://www.faa.gov/air_traffic/flight_info/aeronav/procedures/). Each procedure is stored as a package of PDF files. The Form 8260-3 lists the changes and reasons. There’s also a map plotting the TERPs obstruction areas for each segment. You‘ll see an estimated date when the procedure should be officially charted. Finally, at the bottom of the window, there’s even an email address you can use if you’d like to comment on the procedure.