Couple months back, I shot some very hot aircraft engine enamel over a base of SEM self-etching primer.
As the SEM stuff is pretty much impervious to everything shot over it, you can imagine my surprise when the enamel produced a cracked finish on the broad flat areas, probably just about what you're looking for.
I've seen "cracked" finishes for faux-aging furniture, available in hardware stores too, that intentionally take advantage of adverse reactions of topcoats with basecoats.
Lacquer over enamel is well known to cause wrinkling, lifting, or cracking, and hot lacquer over bare plastic may cause crazing or cracking too.
Just now remembered...last week I shot some Transtar 6183 self-etching green over bare Gunze plastic to see what it would do, and a wet coat generated cracking, again, probably pretty close to what you want.
Problem is that it's not really very predictable, so much experimenting will probably be required to hit your sweet spot.