Here's a Hunter 33 32 P7 drop-swing holster which was given to me by a Highway Patrol Trooper many years ago. (Shown unsnapped and partially rotated.)
Was sorta-OK, especially when driving, since you could unsnap it and allow it to "bend" with your leg while sitting down and driving, but it was still difficult to draw while seated --if needed.
If you watch old re-runs of the "Highway Patrol" series starring Broderick Crawford, you can still see this (or an equivalent) holster on his uniformed Officers. Kind of interesting to watch the holstered gun swing back and forth if they're unsnapped and the Officer is running. (There is no leg tie.)
I used it for a while in the fields and forests with a Smith 19, but discovered that I really, really preferred crossdraw, especially after the advent of seat belts.
In 16 years of working in downtown Denver, I've only seen one uniformed Denver PD Officer carrying crossdraw.
I have a clamshell shoulder rig for my 1911, but I hate it.
Terry, 230RN