Toshiba has just announced the AC100 mobile internet device, and we were fortunate enough to grab one for an extended test over this weekend. While Tosh’s implementation of Google Android is still in development – the AC100 will be released in August – the hardware is final and we were able to get a clear idea of what the AC100 would be like as a day-to-day companion.

And let’s make no mistake: this is a device you can take anywhere. It’s tiny, measuring just 26.2cm wide and 21mm thick at its fattest point (the rear). And it weighs a miniscule 870g. The benefit of the clamshell design over a slate such as the Apple iPad is obvious too – chuck it in a bag and you don’t need to worry about protecting the screen.

What’s fascinating about the AC100, though, is the choice of Google Android as an operating system. Toshiba isn’t the first to opt for this route: Acer produced the Aspire One D250 last year, which dual-booted Android with Windows 7, but at that point we felt Android wasn’t ready for the big screen.

While our AC100 was a very early sample, with a developer version of the OS, it’s already clear that Toshiba has put a lot more effort into making it work with a 1,024 x 600 resolution.

For instance, press the on-screen shortcut at the bottom right and all the available applications fill the screen. These range from Fring (a VoIP service) to Opera Mobile to EverNote (a note-taking tool) to a YouTube player. Most Android applications should work, although they’re unlikely to take advantage of the screen’s high resolution.

One app that will is the special version of DataViz Documents to Go that will be bundled with the AC100. This brings the ability to edit word processing documents, spreadsheets and presentations, although not create new ones. That said, you can convert a Word or Excel document and click Save As, so this restriction is easy to work around. What might persuade you to upgrade to the full version is a lack of a word count and advanced formatting.

There are other nice touches too, including the ability to associate different desktops with the wireless networks you use. So, you can have a home desktop with YouTube and social-networking widgets, and a work desktop with the email client to the fore.

We can also see signs that Toshiba has put effort into making the hardware and software work together. The Escape key doubles up as a Back key, a search key launches the Quick Search tool, while four useful buttons sit at the top-right of the keyboard that allow to you bring up settings, switch between open applications, launch the web browser and switch to the email client.

Another key inclusion sits inside the chassis, with Nvidia’s Tegra processor taking pride of place. This has some similarities with the chip inside the iPad, running at 1GHz and being based on the ARM9 architecture. It proved enough to keep the AC100 feeling nippy, and 512MB of RAM means it’s capable of multitasking without freezing.

Rather ambitiously, Toshiba also includes an HDMI port on the left-hand side of the chassis. An SD card slot and headphone jack also sit on the left of the chassis, with the right home to a single USB port, power connector and a mini-USB port. The latter could be used to synchronise the AC100 with your main PC, just as you would a mobile phone.

These ports are housed in a curious yellow surround, which brings some welcome relief to the dark grey plastic used for the rest of the chassis. If it was any larger, this monotonous finish – despite a hatched, honeycomb effect on the lid – would make the AC100 look rather dull, but being so slim and compact it gets away with it.

Far more importantly, the 10.1in screen itself looks great. We half-expected Toshiba to skimp here and include a sub-standard panel, but in terms of quality it rivals the best netbooks. The keyboard is more mediocre, with bouncy keys that don’t provide much resistance, but the keys themselves are well sized so we had no difficulty typing at speed. The trackpad and mouse keys are big and responsive too.

The final inclusions of note are inside the chassis. It includes 802.11bgn wireless, Bluetooth and some models will integrate mobile broadband. A 1.3-megapixel webcam completes the picture.

So we’re largely impressed by the AC100. If Toshiba can price it right (all we know so far is that it will be “similar” in price to a netbook), then it may carve out a niche in the same way the Apple iPad has – but with the advantage of a more rugged clamshell design and a keyboard.

An awful lot rests on the final software, however, and initially buyers might be disappointed that it comes supplied with Android 2.1. As a result, Flash won’t play, rather denting the AC100’s internet browsing abilities. Toshiba promises an update to Android 2.2 (which will fully support Flash) won’t be too long in coming, and that it will be an over-the-air upgrade.

The AC100 certainly needs this to be a compelling buy, but even in its raw state we’d be fascinated to know what you think: would you buy one? And would it be instead of, or to accompany, a second laptop?