Not quite low carb, but I have found the freezing shepard's pie works really well. I bake then mix sweet potatoes and butternut squash for the top part and sautee sausage or ground beef or turkey with broccoli, carrots, chard, onions, garlic, whatever I have on hand for the bottom. I put them in baking dishes and cover with foil and stick in the freezer and then stick it in the oven for and hour or so the day I want them, they are terrific.
Its also really handy to grill a bunch of chicken over the weekend and you can throw it into all kinds of things. Or I make chicken soup and use the leftover chicken for chicken salad, tacos, whatever. Lately I started processing a big batch of onions and a big batch of garlic and sticking it in the fridge so it takes just minuets to make dinner on weeknights.
I am not sure if this is the kind of food prep that you are looking for, but some ideas that my family likes:
Sunday, make a big pot of chile verde (pork simmered with green chilies), then leftovers in tacos or tostadas, chile verde omlettes, etc.
Good old pot roast (I wouldn't hesitate to substitute yams, parsnips, whatever for the tators!), and then a quick shepards pie or beef pot pies with the leftovers.
Stews, soups, etc that all improve with a day or two are really nice.
Another think I like to do is make double batches of more time consuming meals, and freeze one.