Yeah, I think it comes down to what you consider "legitimate". I had googled this quite a bit about 5 years ago, and what I came up with were the orders that still exist in the church, and a few that are state-sanction in European countries (such as the Order of the Garter).
Modern Orders that have historical precedence, or are state-sanctioned, or are part of the church are still quite numerous (and often very exclusive in terms of who can join).
Modern Orders that were created by enthusiasts, such as our own here, are much smaller in number, but don't fit the definition above. But it still makes me very happy to see groups like the Order of Selohaar, Order of the Fiat Lux, and Knights of Veritas, and other such groups that recreate chivalry and knighthood these days.