I found the coffin pattern through Family Fun. They send me emails with recipes and other fun craft ideas that almost always get my wheels turning! :)
It's not too difficult to assemble, but I recommend using Sticky Strip to hold it together since the double thickness of the card stock layered with DSP will add additional stress to the flaps that hold it together. I used one 12x12 sheet of DSP for the inside of the box. One side of the paper in the bottom of the coffin and the reverse (a purple stripe) on the inside of the coffin lid...looks AWESOME!
STAMPS - Baroque Motifs, All Holidays