Not quite what you asked for, but I use an under desk bicycle rather than treadmill. I cycle most of the day and do some of the day standing up (on a rubber mat

Not quite what you asked for, but I use an under desk bicycle rather than treadmill. I cycle most of the day and do some of the day standing up (on a rubber mat not a treadmill). I love it. The desk cycle doesn't get in the way when sitting or standing. Whatever you choose, I highly recommend getting an ergonomics expert to help get you set up with all of it. Might sound silly but you can really cook your arms, shoulders, back, and knees if you're not careful lol