I have a feeling that what we're going to get will be the T-Shirt and Jacket. I really do.
It wouldn't surprise me if all we get on the show is what we've been seeing so far, I just don't think that should be or will be considered his official Superman costume. The other League members have a costume and Clark will too at some point even if we don't see it on camera. Remember, we've already had two references to a cape.
I think the costume in the pic I posted (or something close to it) would make a decent outfit if something has to be shown and the traditional one isn't used. And I don't see how it looks any more "ridiculous" than either the traditional outfit or what the other League members wear. The Superboy costume I think looks a little too off the mark.