Don't know of anything ready made where you wouldn't have to remove the webbing from the hammock, unless you wanted to carry around two suspensions.
There are set ups available from several different places like this:
Once I played around with a cinch buckle on my Speer webbing. This would require you to attach some rope from the cinch buckle to either a biner or directly through a loop in a tree strap ( would still need a biner or Dutch Hook though), so there would be that much "DIY", which isn't much. Obviously I used way more rope here than I needed, along with a heavy biner, but you get the idea. I would use a much smaller piece of Spider line rope or even some Amsteel and a UL biner if I decided to use this permanently. But it worked just fine. Point is, this approach allowed me to use a cinch buckle with my stock Speer webbing- without having to remove the webbing.