Have gone back to the beginning of this thread and started playing with grayscale imagery again, to see if I can create more detailed maps.
Believe it or not, ten years have passed, I'm still here and still doing "Experiments with LIDAR"!

Still working with grayscale imagery too, but with 1-meter resolution DEM in 3d with my own web app. Garmin devices and software just can't support the maps I want to make anymore.
https://boydsmaps.com/#13.00/40.357081/-77.046754/mbx3dmidatl/69.60/70.20
My web app is free, there's no advertising, no registration and it works on any device.

This has been my most ambitious map-making project yet, ten million map tiles (over 260gb), covering a portion of the US Mid-Atlantic region. Am planning to expand the map to a much larger area later this summer. This is the current coverage

There's also a 2d version of the map which loads faster and uses less data, since there's no 3d elevation data.
https://boydsmaps.com/#13.00/40.991210/-75.132460/midatlidar/0.00/0.00Still using Globalmapper for almost everything, finally upgraded to version 23 this year. My app uses the open source Maptalks API however the 3d maps use Mapbox GL/JS inside a Maptalks container. Has been quite an education, needed to figure most things out for myself as there is not much documentation on building 3d maps from your own data and hosting them yourself.
I put all the DEM together in 32-bit floating point TIFF files which are imported into the Mapbox rasterio command-line program, then exported in Mapbox RGB elevation format. I wrote my own code to read elevation from these files and show it in a realtime "heads up" display on the map.
As a companion project, I used NASA ASTER 1 arc-second DEM to make a lower-resolution 3d map covering all of North America. Used USGS National Landcover Dataset and ESA Worldcover data (outside the US) with my own pseudo natural color pallete to produce a more "artistic" 3d view, along with atmospheric effects.
https://boydsmaps.com/#12.80/44.099767/-71.572680/mbx3dnalc/48.60/76.80This was more of an "art project" for fun, but the elevation data is used in the same way as the other map, providing a realtime elevation display anywhere in North America as you move the map around. Still a big project, but "only" about 4 million tiles / 100gb.

There are over 200 other maps available in my app, from servers in many different US states, Canada and even Switzerland. Also OpenTopo, USGS National Map, live weather forecasts and radar plus a number of maps from HERE (the company that provides data to Garmin for City Navigator). I support waypoint import/export in Garmin-compatible GPX files, plus my own format that can be customized and imported/exported in Excel. Not supporting tracks yet, but will get around to it eventually.
Anyway... that's what I've been up to. How did
you spend the last ten years?

Is anybody from this thread still here? Quite a nostalgia trip revisiting it now, I do miss the old days.