I’ve got a Surly clone that I adapted to push up by removing the B-stop pin and switching the spring with a push up one from Charlie The Bikemongers shop.
Fitted it along with a half link so the chain is almost the correct length and then just set the tension.
Works absolutely perfect once set up (have to get it all in-line and then it goes quiet) but as it has a loop over the chain to keep it on the pulley it is a pain when taking the wheel out. I have an old chain device I picked up at a bike jumble with a jockey wheel that slides up and down to change position for different rings so I am going to cut the top bit off that should go to a guide and turn that into a tensioner that can be undone with a multitool instead of needing to undo the BB shell. I’m only doing that for neatness – no other reason as the push up works fine.
edit: another option is just use the powerlink in the chain to remove the back wheel. If you undo them regularly they won’t get stuck out on the trail. Should be able to get just enough slack.