I know that not everyone has access to Knit Picks yarn. I'm going to start compiling a list of possible yarn substitutions for Sheldon and post it here in the future, so if you have a suggestion, I'm all ears. Meanwhile, the wonderful Nicola Hickson of London has test knit Sheldon in Sirdar Snuggly Baby DK, and he came out fabulously. She used 4mm. needles and got a tension of 22sts and 28 rows over 10 cm, 1 ball each of colors 350 and 242. Thanks to Nic for test knitting and for sending in this great photo!