Tesla facility in Lathrop, California

Tesla Motors has a secret. The California automaker has leased, and is now renovating, a 431,000-square foot former Daimler-Chrysler distribution facility in Lathrop, CA, but is not saying exactly what it will be using the space for. At least, not yet.

Interior shot of Tesla's new leased space in Lathrop, CA.About an hour's drive east from its Fremont, CA factory, the property is located just off the north-to-south Interstate 5 (I-5) and has extra acreage to expand the building by another 124,980 sq-ft, if needed. Designed to handle a lot of shipping in and out, one side of the structure is gifted with 32 truck docking bays.

With no official word on the type of activities that are planned for the facility, it is only natural that we would want to speculate a bit. There is one clue out there that can aid our hypothesizing. The job section of the company's website lists a number of openings that would indicate manufacturing of some sort is intended for the space.

We'll go ahead and rule out serial vehicle production, since the Fremont space still has ample room for that activity to handle the upcoming Model X and the more affordable future vehicle. It's far too small to be a battery gigafactory, so could it be instead a kilofactory ? Probably not. Of course, it could just be a new site for producing components for the Fremont production lines, but that doesn't sound nearly as exciting. It also doesn't seem to be worthy of secrecy. The coolest – though not necessarily most accurate – thing we can come up with is a skunkworks. A secret lair where new concepts are conceived and developed away from the prying eyes of the public. Yeah, we'll go with that.

When we contacted Tesla for clues about the facility's purpose we got a boilerplate response, though interestingly, they might have thrown us another mysterious bone in the process. And we quote, "Tesla is continuing to invest and create jobs in California as part of our ongoing infrastructure expansion. In the last two months, we have signed leases for more than 625,000 square feet of Californian real estate, independent of sales and service centers. These recent investments reinforce our commitment to California and will help us continue to bring compelling electric vehicles to market at affordable prices."

With a 194,00-sq ft discrepancy between the known Lathrop acquisition and the numbers given by the automaker, it seems that may be yet another decent-sized unknown building in the mix. It's all enough to boggle our easily-beboggled minds so, to paraphrase a certain Tom Waits, we ask you, dear reader, what's he building in there?