Here is a pair of classic style pajama pants from Primark. They use a large checker pattern in red & yellow, and fill it with classic logos, & various Sonic artwork. The artwork seems to have a good variety, and likely includes 'redone classic style' art as well. This retails…
Pajamas These are also available in the UK. The design is not painted on at all, rather it's dyed in there for sleeping comfort. There should be a Sonic on the pants somewhere, but Gear doesn't own this. Sizes are unknown.