Yes unfortunately 'ole Scorponok has never been re-issued and to be honest mate, I wouldn't waste my money on a KO.

I utterly adore this toy, my own owes me about $500 all up as I had to piece-meal him to completion; He's 100% complete, right down to his accompanying paperwork and a fresh set of Reprolabels reproduction stickers, but I went about acquiring him to a level and by a means that may be a bit off putting to a number of people.

That should give you a bit of an idea of the possible investment you're facing, in-lieu of an Official re-release and if you choose to avoid KOs - It can be done (And probably cheaper too), it just depends on how much you want him dude.