Sony Ericsson has unveiled two upcoming feature phones for the first time by announcing a contest on the social network. Twelve finalists will get the chance to review one of the phones, and the winner will receive ten of that model to dole out to friends and family. The contest forces you to guess the names of the new devices, but speculation is pointing to txt pro and Mix Walkman. We know one is Walkman-branded and the other is a smaller slider phone geared toward messaging; they appear to be the CK15i and ST18a we saw leaked a few days ago, although both are eerily similar to the Xperia Mini and Mini Pro. Since these handsets are being considered "feature phones", we're unsure if they'll actually be shipped with Gingerbread or a watered-down variant. We'll find out all the details no later than June 7th when the selected videos go live. If you're hoping to be the brains behind one of them, submit your entry by visiting the source below before May 26th.