Josh Miller/CNET

After a week of intense interest in what Google has been building on barges in the San Francisco Bay and in Maine's Casco Bay, the mystery may well be over: The tech giant is developing a reconfigurable, invite-only showroom for Google X-related projects and products.

According to a report from CBS' San Francisco affiliate KPIX, Google has been working on the project for more than a year, and the plan is to make the showroom movable and also capable of being taken apart and reassembled as needed. The idea is that elements of it could be on the water one day, or on a ski slope the next. The edifice will have three floors of showrooms and a party deck, KPIX said, citing "a source who has been on board the vessel."

KPIX also reported that the project has been "personally directed" by Google co-founder Sergey Brin.

Google X is the tech giant's secretive research unit. Its efforts have ranged from the Google Glass computerized eyewear to Google's self-driving cars, and last spring it acquired Makani Power, a startup investigating far-out, high-flying ideas for wind power generation.

Last week, CNET was first to report the connection between Google and the mysterious four-story building, made from shipping containers and covered in scaffolding and black netting, that is sitting atop a rusty barge alongside the former Navy base at Treasure Island in San Francisco Bay.

At the time, CNET reported that Google was likely planning to use the structure as a floating data center. But subsequently, a KPIX report and a tip to CNET both indicated that it would be used as some kind of floating Google Glass store. (KPIX is owned by CNET parent CBS.)

Although Google has been working on the structure for months, first inside the cavernous Hangar 3 on Treasure Island, and then outside that building but behind security fencing, it hasn't said anything publicly about the project, nor has it confirmed its involvement. But both the National Park Service and the San Francisco Bay Conservation and Development Commission (BCDC) confirmed Google's involvement to CNET, though neither agency could say what the tech giant was building on the barge.

And although activity on the project was bustling at one time, it has recently come to a complete standstill.

Across the country sitting idle is a second mystery Google barge that in early October was towed into the harbor in Portland, Maine. The registration on the Portland barge showed its owner to be By and Large LLC, the same company that owns the barge on which the Treasure Island project was built and that also is the leaseholder on Hangar 3. CNET was able to connect the projects on both coasts to Google.

It's isn't clear why work hasn't resumed on Treasure Island. The BCDC has said it isn't ready to issue a permit for Google to move the barge to San Francisco's Fort Mason -- a desire confirmed by the National Park Service, which manages that former Army base -- but BCDC didn't stop the project. Asked if it was responsible for ordering the work stoppage, the Coast Guard also said no.

Google hasn't responded to numerous CNET requests for comment. And in the absence of other public agencies with any knowledge of the project talking, it has been impossible to say why there's no activity at the Treasure Island site. But the Coast Guard in Maine did say that the assumption there is that work will not even begin on the structure that pulled into Portland harbor until the San Francisco Bay-based project is completed. And now, KPIX reported that Google's problem is that it didn't seem to expect that the Coast Guard would consider the project to be a vessel, and therefore subject to marine regulations.

Work likely began on the San Francisco barge project sometime last fall, given that Hangar 3 was leased starting in mid-November 2012. According to The Day Connecticut, work on the East Coast mystery barge structure started sometime in May, although the containers used to assemble that structure were built in San Francisco. That work almost certainly took place in Hangar 3.

Now, the biggest questions are whether Google will confirm the new KPIX report, and when work will start again on Treasure Island. But with the mystery revealed, it's safe to wonder if much of the intense speculation and interest will quickly die down.