Here are some plans for a DIY wooden hand rocker used to aid in fast forced carbonation of a corny keg. It can be used on a table or counter by hand(two fingers) or on the floor with your foot. Takes 10-15 minutes to get the keg fully carbonated.
How it works: Strap in the keg, attach co2 set to 30psi and gently rock for 5 seconds and then wait a few seconds until it stops gurgling. Repeat until there no more gurgling and your done.
Drop to serving pressure, connect to a tap and your good to go. My typical serving pressures are 10-15 psi for home-brew and 30psi hard seltzer and water . Your mileage may vary...
image below is a 1:1 template you can printout with scaling to fit on (3) 8-1/2 x 11 pages, uses 1/2" grid with 11" major tics.
I also have a laser cutter *.svg file available, but haven't figured out how to upload it, yet.
If there's any interest I'll pursue it further.