Ok, for those that wanted to know how it turned out:
I used 2 standard pillow cases for the pellets; sewed 5 columns and filled each with 2ozs of pellets, sew that line up, and so forth, did about 5 rows...forgot sorry! I sewed them together. I then made a cover for it and this is where the issue came in. I should have left at least an inch on the pillowcases with no pellets because in order to secure to the cover I had to try not to hit a pellet. A removable cover would be great but unless it is super tight, then the pillowcases shifted. So what I did was fold the top of my blanket down to cover the top of the pillowcases, which luckily had a large area with no pellets. So the bottom would not move, I felt around for the bottom part and tried to sew at least 3 areas securely to keep the cases from shifting. I will have to re-think my plan for the next one but at least Little Bit seems to like it right now. It was storming so I put it on her and she stayed calm for the most part.
I will try to get a picture tomorrow.