New O-Class filings for 'motor vehicles and motor vehicle engines' allow us to don our speculation boots. Everyone, get your sleuthing caps out. They look great too.

The filings for various Mercedes-Benz O-Class models have been made with the European Intellectual Property Office on February 4, 2019.

According to AutoGuide, the company has filed trademark applications for O 120, O 140, O 180, and O 200 model names.

It's not known what type of car the O-Class name might be used for, but the indicative power badges suggest it would be a vehicle would be smaller than the A-Class, which begins with the A160 petrol and A160 CDI diesel.

The lack of a diesel variant leads us to think it might be an updated and rebadged version of the Smart ForFour and, possibly, ForTwo.

Renault recently unveiled the facelifted Twingo range. The Twingo and ForFour share a factory, as well as their rear-engine, rear-wheel drive platform.

Smart is set to be relaunched as an electric-only marque in Europe by 2020. By shifting the ForFour and/or ForTwo over to the Mercedes-Benz stable, Daimler will be able to keep its promise, while also continuing sales of the petrol-powered variants.

Another alternative is a vehicle to slot in between the Smart range and the A-Class. If such a vehicle is being planned, it will likely be based on an existing platform, probably a shortened version of the front- and all-wheel drive architecture used for the A-Class, CLA and others.

Of course, it's also possible the O-Class may never see the light of day.

This is not the first time Mercedes-Benz has used the 'O' name, with O530, O530G, O530K and other badges currently used to differentiate variants in its Citaro bus range.

Where do you think the Mercedes-Benz O-Class might fit into the company's ever-expanding range? Let us know in the comments section below.