The FCC sometimes gets a peek at hardware and reveals nothing but a model number to hint at what's passed through its labyrinth. The latest filing leaving us scratching our heads is for the ASUS P1801-T, a "tablet" which could be the final version of the Transformer AiO prototype we saw back at Computex. How did we arrive at the AiO? Well, the model number is a possible clue -- ASUS' Eee Slate B121 has a 12.1-inch panel, so P1801-T may point to this device having 18 inches of screen. As ASUS' dual-OS prototype all-in-one is the only (sort of) tablet we've seen with roughly that many inches, we assume the company is getting paperwork done before a proper launch at CES 2013. A "P1801" running Android 4.1.1 has also popped up at GLBenchmark, with Tegra 3 graphics and thus a Cortex-A9 CPU inside by default. If ASUS is keeping two OS's as per the AiO prototype, that processor caters for only one Microsoft product -- Windows RT. We'll just be kept wondering until we hear something official, but at least for us, an 18-inch Android / RT super-tablet and part-time desktop sounds like it could be a hard sell.