I recently got the "Hex" brand sleeve for my SP3. I really like it... it has the "stiff" kind of nylon on the outside (ballistic nylon?) and a soft fuzzy inner lining. Since it was purpose-built for the SP3, you can imagine that it fits perfectly. There is enough room to fit the SP3 with type cover and pen/loop in place. Although, I'd have to admit, that I probably wont keep the pen in the loop while in the sleeve (to prevent me from accidently tearing off the pen loop tape). The whole thing is about 3/4" thick with the SP3 in the sleeve. I did not take a picture with the AC adapter in the side pocket, but you can image an obvious bulge. I got mine at one of the Microsoft stores, but I'm sure you can get it online somewhere cheaper than the $40 bucks that I paid (although I did get a student/faculty discount!).