Starting Wednesday, Sept. 1, if all goes according to plan, you will be able to order one of the first in what will surely be an avalanche of Android-based tablet computers. That's the day the eLocity A7, running Android 2.2 and based on the Nvidia Tegra 2 chip, will be available for pre-orders at Amazon.com.

The A7 comes from a little-known Philadelphia-based start-up called Stream TV. The $399 tablet has a seven-inch screen and will come with a wireless keyboard and other accessories. It is currently scheduled to begin shipping on Nov. 1.

eLocity A7

I got my mitts on a preproduction A7 very briefly late last week -- just long enough to get a few quick impressions.

It's pretty impressive, in a rough-hewn sort of way -- not unusual for presale units. The device is 8.2 by 4.8 by 0.5 inches in size and weighs a touch over 1 lb. It has a 1.3-megapixel front-facing camera, a microphone and a 3.5mm headphone jack. It supports 802.11 b/g Wi-Fi and Bluetooth 2.1. Its ports include a USB 2.0 jack, a Micro SD slot, a docking port, and -- most interestingly -- an HDMI port. While 3G will not be included with the first units, the company said it is planning 3G capability for a later model.

The HDMI connection, along with the graphically strong Nvidia chip, makes the A7 interesting. The tablet, which has a three-axis accelerometer, can be used to play games with 1080p video. The company has demonstrated a racing game that -- allowing for preproduction hiccups -- impressed. It should be possible for the tablet to show HD video in full resolution -- or you could connect it to an HDTV and use that as a monitor.

Given that the A7 uses exclusively off-the-shelf hardware and software, I asked Stream TV's CEO, Mathu Rajan, whether the commoditization of tablets is already underway even though the market has yet to be established -- and how Stream TV planned to differentiate its offerings in the face of such commoditization. Rajan said that, while the A7 would ship with the standard Android 2.2 interface, his company was working on a software layer that would present a proprietary interface to the user, essentially hiding the Android underpinnings. He said it would be ready for previews before the end of the year.

Incidentally, apps for the A7 will not be available at the Android Market, but at an app store known as GetJar.

For now, the A7 is more interesting for what it represents -- the ready availability of Frankentablets made from bolted together components -- than for what it can do. There's a long history in the technology business of small shops rushing to get their hands on interesting components -- like the first Pentium chips -- and hurrying products based on them to market for pride of place in being first.

Most of them have no ambitions beyond that, and soon vanish. Some of them, like Dell in PCs or Mio in GPS systems, turn into something big. Which way Stream TV and its eLocity A7 go is an open question.

If only by virtue of timing, the A7 demands attention as the harbinger of a new market.

Dan Rosenbaum, by day a search strategist and content maven, has been reviewing mobile technology since the 1990s. His MicroTAC and StarTAC phones are still in a box somewhere.