EDIT: This thread refers to the 2010 product line of foam craft eggs. The manufacturer has made some changes to the eggs for the 2011 Easter season. So for more current information, check out this thread:
Foam Easter Egg carving (2011 product)
Okay, so they're not pumpkins, but they are foam, so the same rules apply. This new item was recently brought to my attention, and it's worth a look. Michaels craft stores are currently selling hollow foam eggs, specifically for carving like pumpkins:
They're about 10 inches tall and 8 inches wide. Circumference at the fattest point is a little more than 25 inches around. Carvable surface area on one side is a max of approx 8" x 6" so designs would have to be a bit smaller and/or simpler than the typical pumpkins many of us carve.
They have a flat spot on the bottom and on one side, so they can stand upright or be positioned on their side, without rolling away. This flat area is only about 2.5" wide. So if we are meant to light these carved eggs, I'm not sure what they would expect us to use. Most battery powered lights I have are larger. Maybe just the small LED tea lights?
I quickly cut some random shapes into the bottom of one egg to see how thick they are, and to get a feel for how well they can be carved. With no cleanup, this is the result from the Versa-tool heat knife (the bigger shape) and the ZP Pro Carving tool with small blade (the smaller hole).
The foam feels more dense and thick than the pumpkins Michaels sells in the fall. I'm not sure why they made these egg shells thicker (about 1 cm or 3/8" thick), since a thinner shell would be easier to cut into.
Also it's worth noting that the eggs are coated in colorful paint (possibly latex based) that can peel back from your cut edge, depending on how rough you are with your cutting.
I'm guessing this is a trial year for this product, to see how the public responds. I'd prefer for the eggs to be larger (they actually have a couple smaller sizes available) and for the shell to be a bit thinner. But there's some potential here.
I can see various approaches in technique. I'm thinking you could probably sand the cut edges when you're done, to smooth them out. And if the paint peels too much (or you find pastel pink to be way too cutesy for your macabre tastes) you could also spray paint them a different color when you're done.
Anyway, that's my take so far. I have a couple of these eggs in the lab, and I intend to play and see what I come up with. I look forward to seeing photos of your egg carvings if you give them a try. And if you have suggestions for how we can best use these eggs, I'm all ears.