M0k3 used to run a square miniature baffle about that size using DPA 4060s, mostly up front or on-stage. It was a DIY setup, I don't think there is anything commercially available that small. For proper shadowing effect, the capsules should be mounted closer to the faces of the baffle than with a full sized Jecklin-disk. There used to be a bunch of photos of his mini-Jecklin variants in the various J-disk threads here years ago, but they might have gone away with the great-purge.
The small baffle works and is significantly more practical in many situations. But Tom makes a good point and I prefer a larger baffle allowing for more spacing between microphones. Even a full sized Jecklin isn't big enough to allow enough spacing IMO. Jorg himself moved toward using a somewhat larger disk with increased spacing over the "Standard Jecklin disk" arrangement he is known for. I have in the past considered using two separate miniature baffles- one for each microphone, allowing closer microphone to baffle spacing on each side but with increased spacing between the two microphones. I suspect that might work best of all, but never figured a good way to rig it and never built the small baffles. I did build an over-sized single baffle which would allow the spacing I wanted, but it was grossly impractical and I never ran it. It's pictured in one of the Jecklin DIY threads here.