Thanks for the replies. If anyone's interested, here's what I did:
1 each pork liver, heart, kidneys
1/4 lb home-cured lardo
1/4 lb fatty trimmings from pork loin chops
3/4 cup bread crumbs
2 Tablespoons Penzey's Bratwurst seasoning
1 teaspoon Penzey's Italian Sausage seasoning
I chilled all the meat before grinding it, one ingredient at a time, in my food processor. I used Alton Brown's "10 pulse" hamburger grind for the heart, loin meat, and lardo. I went further with the liver/kidneys but stopped short of making them into a paste.
Once all the ingredients were ground, I mixed them together with a rubber spatula in a chilled bowl. Then I fried up a small patty to taste for seasonings, adjusted, and let the mixture sit in the fridge for a couple hours.
Next I lined a pyrex loaf pan with plastic wrap and filled the pan 3/4 full with the meat mixture. I then embedded a probe thermometer, closed the plastic wrap over the loaf, and baked it in a hot water bath (loaf pan in roasting pan full of water) until the internal temperature came to 150 degrees.
Then I removed the pan from the water bath, set it on a rack to cool, and set another loaf pan on top with 10lbs of dumbells inside. When the terrine had cooled to room temperature (probe thermometer still inside), I transferred it, weights and all, to the fridge overnight.
The result was a rich, mild terrine that will appeal to people who don't love organ meats. It goes great on a simple sandwich with mayo, good mustard, and homemade pickles. Next time I'll probably get fancier, with more exotic seasoning and maybe some veggies. For my first try at a terrine though, I'm pretty happy.