I was just on the 449 last Thursday and they also offered a "cold meal service" for the lunch out of Boston.
About an hour out of Boston we were called down to the cafe car where the rear section was setup for lunch for the sleeper passengers only (table clothes, table settings, etc.). So, it was more than just picking something from the cafe menu and sitting there.
The menu for lunch offered 2 selections. I didn't take a photo of the menu, but from memory they were:
Cold Chicken Sandwich - consisted of chicken breast with spinach and Parmesan cheese on a ciabatta bread roll. Side was a chick pea salad.
Cold Asparagus Salad - consisted of a grilled tomato, lettuce, diced cucumbers and asparagus spears.
Dessert consisted of a chocolate brownie with chocolate mousse or strawberry shortcake.
Was traveling with my son, so we selected one of each. The chicken was good, but the roll was not too edible being as cold as the chicken. The salad was pretty good, in my opinion. Unfortunately, if you're traveling with a child they didn't have an option on the menu that was kid-friendly.