Mulberry farms sells different sizes of superworms so you could give that a try. They also sell horned worms, silkies, butterworms and phoenix worms too. I usually get my phoenix worms from phoenixworms.com though because they have larger quantities and since even the "large" phoenix worms are pretty small, Tashi goes through them pretty fast. They are a good staple though so I keep getting them.
This is the first time I;ve bought superworms, and I bought the small ones even though Tashi is 17inches long and 15months old. The regular sized superworms freak me out but ofcourse they are the ones that are the most available from the local pet store! Tashi doesn't seem to care for the supers though so I;m glad I only got a small 100 container. Some pet stores will carry waxworms too, and they are soft and squishy, but should only be used as a treat cuz they are high in fat.
Phoenix worms are great and have the perfect calcium
hosphorus ratios, so no dusting required. They are easy to keep (stay at room temperature) and even if they turn black they are still good. In fact that is supposedly when they have the most calcium. Even the "large" size is pretty small though, so Tashi tends to eat tons at once. In fact, he often forgets to chew and then they come out whole in his poop sometimes. I've had to feed only 10 at a time so he slows down and doesnt inhale!
Horned worms are kinda expensive, and they get HUGE, (see pic below) but they are soft bodied and sometimes squirt when they are eaten! EEEWE! Tashi LOVES them and will literally jump off his basking spot and dart to the other end of the viv when I drop one in! Bonus is that you can stunt their growth by cooling things down if you don't want them to get too big for your beardie.
Butterworms are a good soft bodied worm too and are a good staple. They are kinda reddish orange caterpillars that don't get as big as hornworms but are much more plump than phoenix worms. You can keep them in the fridge. They arent as wiggly as phoenix, but they are another one of Tashi's favorites.
Silkworms are, in my opinion, a pain in the butt to keep. They are great for your beardie, but are very high maintainance for you. I've only purchased them once, and they were all clumped together and damp so I felt like I was just giving him a blobby mass of worm goo. Blech!
Anyway, I hope that helps a little. Sorry it is so long, but this is just my experience with those worms. Oh! And I think another poster said this too...don't let your beardie get spoiled with worms. We almost made that mistake with Tashi. We always fed him crickets too, but once he got a taste of those worms he wanted to lose the crickets all together. I swear they are bearded pigs not bearded dragons!
~Jill