Sometimes it's hard to keep track of small electric-vehicle companies, most of whom are likely to vanish without a trace within a few years.

But T3 Motion, an EV startup in Costa Mesa, California, has a gimmick: It uses an Apple iPad to provide driver and passengers with audio, video, games, and vehicle navigation.

To help with sometimes finicky reception, its GT3 electric car even has a built-in antenna for 3G signals.

The GT3 itself is said to be a two-passenger vehicle with a 70-mph top speed and range of up to 100 miles.

No price or timing is offered, but T3 Motion is now taking pre-orders on its  website. Ahem.

Still, the idea of replacing much of your dashboard with a personal digital device seems appealing. GM provided a digital-device dock in its Project P.U.M.A. two-seat, two-wheeled autonomous electric urban transport concept in April 2009, to do many of the very same things.

But there are challenges. For one, carmakers operate on longer product cycles--cars are redesigned or replaced every four to seven years, and it takes three to five years to do it--than do consumer electronics makers, whose products are renewed every 18-24 months.

The challenge: How does a carmaker know three to four years in advance what products Apple and its competitors will come out with? What if the product they've designed into your car flops (e.g. Zune)?

And how does a carmaker ensure that your device stays operational over the 15-year life of a car?

Apple desktop machines have a usable life up to 10 years, but they're only supported with security and software updates for 5 to 7 years. And mobile phones have a shorter average life yet.

And what if your iPad gets stolen: Can you still operate your car?

Unless or until a standard, universal interface is jointly agreed to by the global consumer electronics and auto industries, we suspect we'll continue to get only minimal interfaces to external devices. (Ford is the U.S. market leader here, with its Sync and MyFordTouch systems.)

Consider the decade it's taken to get MP3/iPod controls into cars. And consider that digital equipment has traditionally been a profit center for automakers, so offloading it to Apple could actually cut their margins.

In other words: We're not holding our breath.