...which we've been able to do since the release of the 313/315 packs (possibly earlier, depending on how *exact* you want the TSO to be)....granted it'd involve a little bit of reskinning and possibly a change of couplings but nothing beyond the limits of the reskinners amongst us. Probably hasn't happened because there's been no clamour for it from the masses.
Just out of interest.. do either of the two base packs for this enhancement feature the early internal cab view?