Trifle variations are infinite (even more so when you substitute sponge cake or gingerbread cookie pieces for the brownies and use different pudding flavors). Here are some of the brownie variations I've tried.
Make mocha brownies (your own found recipe or ask for the one I use)
Instead of using two cups milk in the pudding, use 1 and 1/2 to 1 and 3/4, substituting super-strong, brewed, cooled coffee for the remainder.
Garnish with chocolate curls and chocolate-covered coffee beans.
Make minty brownies.
add mint extract to the pudding, if desired (whether chocolate or vanilla)
layer in Andes Candies and garnish with the same
Etc, etc., etc.
I haven't tried a peanut butter variation yet, but I bet that would be yummy.