Is there some specific reason you think coins would be immune to shorting? This sentiment seems to come up frequently, but shorting is something you can do with basically anything that holds a value over time and is (sigh) fungible, because at its core it's just a transactional set of promises ('borrow' asset, sell asset, buy asset again at your target date, 'return' new assets).

If anything, the modern round of coins with smart contracts are probably uniquely suited to shorting, or enabling the shorting of other coins.