The tablet device market is heating up as more and more companies are looking to take a bite out of the iPad’s overwhelming share of the market. Hewlett-Packard is one of them, and we’ve learned it may be prepping to launch yet another tablet after launch of the 9.7-inch webOS-powered TouchPad.

A story in the Taiwan Economic News reveals that the technology giant has ordered 400,000 to 450,000 TouchPad tablets per month from supplier Inventec. The manufacturer will also provide HP the new 7-inch tablet, presumably also running the company’s platform.

As CNET reports, “an industry insider cited by Taiwan Economic News says that HP will order around 3 million tablets from Inventec this year. Beyond the August kickoff date, no details were revealed about the 7-inch tablet. A request to HP for comment on the prospective tablet was not immediately returned.”

HP is set to launch the TouchPad this Friday, with a price tag of $499.99 for the 16GB model and $599.99 for the 32GB model. Similarly, Another tablet launching this Friday is the Android-based HTC Evo View 4G, Sprint’s first tablet. The device is the first Android tablet capable of supporting Netflix streaming, and comes alongside a handful of other Android smartphones with the same capacity.

But the iPad is dominant in the tablet market for a reason.  It’s software is designed to work with its device, and its uniform approach to marrying the two experiences has given Apple a head start in the tablet market.  While HP is to take a similar approach to its webOS/TouchPad team up, Apple’s developed a large user base around its products, learning from each iteration of iOS and setting high standards for any tablets that come after.

The fragmentation of the open-source Android OS is the primary reason why users of certain devices can’t fully benefit from particular services and apps. Netflix reportedly had to do some extra research to facility its launch on the Evo View 4G, which gives it an edge over Hulu that have yet to reach any Android tablet.

webOS and Android are expanding in more areas than one, yet – at least for now – the iPad remains the undisputed ring leader. According to comScore, 53 percent of non-computer device traffic comes from Apple devices. The iPad accounts for 21.8 percent, or 89 percent of global tablet traffic.

Even as the tablet market gets more crowded, it will be some time before any other single device can live up to a self-proclaimed title of iPad killer.  The secret weapon will be the OS, coupled with a wide range of consumer devices to diversify away from the iPad’s uniform approach.  As we saw with smartphones, it is possible to topple Apple from dominate market share.  At this point, it’s a matter of which competitor wants it the most, and what lessons they’ve applied from the smartphone ecosystem.