That's like asking if Linux has a desktop environment. Strictly, no, but Linux distributions do. So OpenIndiana has MATE and a couple of other options; Tribbli

That's like asking if Linux has a desktop environment. Strictly, no, but Linux distributions do. So OpenIndiana has MATE and a couple of other options; Tribblix has about 30 desktop options; OmniOS you can install a desktop stack from pkgsrc.