Right now, Tesla's impressive Model S is the only serious all-electric luxury car. But there are more and more signs that legit competition for Tesla is on the horizon. Photo credit: Tesla Motors.

Tesla Motors (TSLA 1.97%) has wowed the world with its first mass-produced model, the all-electric Model S luxury sedan. It's a superb product. But the Model S is expensive: Even the most basic versions cost more than $60,000. Tesla CEO Elon Musk says his company will have a more affordable model in a few years -- but will that model be playing catch-up from the start?

It's looking possible. From the start, sophisticated investors have viewed Tesla's prospects warily, worried about competition from the world's automotive giants. Tesla has brains, guts, and momentum, no doubt -- but the big automakers have resources that Tesla won't be able to match for years, if ever.

So far, that competition has yet to materialize, but there are more and more signs that it's coming. The latest: General Motors (GM 0.45%) said this past week that it's working on an electric car that will have 200 miles of range -- and cost just $30,000, a price that will challenge (and might even undercut) the upcoming "affordable" Tesla.

Of course, it's one thing for any company to claim that it's "working on" a breakthrough product, and another thing entirely to deliver it. Tesla's track record to date inspires some confidence. How seriously should we take GM? In this video, Fool contributor John Rosevear takes a deeper look at what could be coming from GM -- and at the likelihood that the Rust Belt giant could really trump Silicon Valley's auto darling.