Ken Penders has put up some lovely covers of the Sonic Adventure adaption for the Archie Comic book. Only 2 (Sonic 80 & 81) work at the moment, the rest will be up soon. since he Knuckles/Sonic books colliding, i **think** the 80 cover is much different than before. Go see them here
Also Ken has put up a preview of Knux 32. the Last Knuckles Comic of the lot. see it here
Source: Ken Penders Page