It's possible that the Khajiit looking more muscular than we're used to seeing is just because this particular Khajiit is like that, after all, we've been told that body customization is in, so most likely, all races can have both skinnier and larger builds. What we see here may simply be an example of that rather thsn a sign that Bethesda has gone with a different type of Khajiit, obvious, since this is the only Khajiit we've seen, we have no way to know if all Khajiit are more muscular or just this one, however, it certainly seems like a possibility, and I think a likely one as I expect Bethesda to keep Khajiit as a stralthy race, because let's face it, when most people who have played Elder Scrolls games think of Khajiit, that's what they'll think of, I'm sure.
That sounds pretty reasonable. I had forgotten that you could customize body appearance too. Anyways, either way I'm making my first character a buff Khajiit fighter.
Or maybe a fearless Nord barbarian. Or perhaps a savage Orsimer berserker. That is to say, until the other races are released and I see how epic they look.
Dang, too many choices, and they're all so awesome!