The mystery of the Nexus One continues to grow ever deeper, but we can pretty much confirm Google's planning to sell something under that name: the search giant filed an intent-to-use trademark application for "Nexus One" on December 10th, and in order to be granted the trademark registration it'll have to use the mark in commerce at some point in the future. Now, don't get too carried away -- sure, that could mean free unlocked GSM Android sets for all, but it could also just mean Google's planning to sell the Nexus One as its next-gen Android Developer Phone. Considering everything we've heard points to the device being limited to T-Mobile 3G, we'd say the developer phone theory is still the most likely, but it's all up in the air until Google provides a sample of the Nexus One mark being used in commerce to the USPTO -- or, better yet, announces something official.Ruh roh. As we're sure you're aware, the "Nexus" name is a riff on Philip K. Dick's Nexus-6 replicants in Do Androids Dream of Electric Sheep? and ultimately in Blade Runner -- and his estate is none too pleased that Google's using it without permission. According to the New York Times , Dick's daughter -- who is in charge of licensing his work -- was never told of Google's plans, and she's contacted the lawyers now that she's found out. We're guessing Google can still make nice though: she says she would have been open to an agreement had contact been made earlier. So... let's get on that, guys.[Thanks, Amit]