I feed my 13 1/2" beardie medium to full sized silkworms and she has absolutely no problem digesting them or swallowing them. She poops every day and takes small bites when she eats the bigger ones. One big silkworm is a lot more food than one cricket (probably a 2-3" silkworm = 10-15 crickets). I feed my beardie 1 big one and a 3-4 medium sized silkworms a day and 15-20 crickets a day. She gets 1-2 waxworms a day if I buy them as a treat. Silkworms are better feeders than crickets, although I hear dubias are really good, too (not really down with breeding roaches at the moment). Silkworms apparently have an enzyme that helps absorb calcium and reduces arteriole plaque, plus they have a low fat content, high protein content and no chitin to bother digestion.
I think a baby might have a hard time eating really big silkworms, though. I won't feed Kiyo goliath worms until she's full size for this reason (although I can't wait and I bet she can't, too!). I wouldn't feed babies under 12" anything bigger than the medium sized ones (1/2 inch to 1 1/2 inch). Silkworms don't have a shell made out of chitin like crickets or dubias, so you don't exactly have to follow the "smaller than between the eyes" rule as strictly.
Some links:
http://www.mulberryfarms.com/ This is where I get my silkworms. I live in Los Angeles so it's actually easier/cheaper to find buckets of mixed ones in pet shops.
http://www.beautifuldragons.503xtreme.com/Nutritionframeset.html A lot of people have recommended this website to me for figuring out what to feed your beardie. Really great website!
