I made the mistake of giving away too many last year, saving enough for one batch for me to start with this past spring. But, my silkworm chow went moldy and I lost the whole batch. I have ordered from Sericulum and Mulberry before...
Sericulum is great but a little pricey, but for some reason, they're ordering system has been down for a long time. I click on the page and I get a system error. I don't know what's up with them but when I sent them an email, I didn't get an answer and I can't find a phone number.
Mulberry farms, I had trouble with. They glue the eggs down to a petri dish causing all the eggs to hatch in a mass. I ended up losing more than half of the hatchlings simply because I was unable to move them onto fresh food as they hatched. Grating the chow on top simply does NOT work. It just squishes the babies and polutes the entire mass.
I've had horrid luck with silkworm chow. I'm about ready to throw it all out. I lose more caterpillars with it!
I usually rear silkmoths all summer but this summer, I've been concentrating more on reptiles than bugs. Each summer, I would swap bombyx mori eggs with a penpal I had so that we could keep our variety in our stock but it seems I've lost touch with her. 
I'm so mad at myself for giving so many away...but that's just how I am. I had a nice variety of peach, yellow and white cocoon spinners, "zebra" cats too. Does anyone have any silkworm eggs they'd be willing to share, please? I don't care what color...I just want to get a colony going again.
By the way, in my searches today, I found 3 canadian suppliers. I recall that a couple people have asked for Canadian silworm sourches. If anyone needs help finding them, speak up and I'll try to track them down again. 
