IBM claims to have created new species of custom-built, industry-standard, Linux-based rack server for Web 2.0 and Cloud Computing companies with massive data centers and tens of thousands of servers, like online gaming, social networks, search and Internet firms.

A relatively limited marketplace of maybe a thousand companies with fat wallets capable of shelling out tens of millions for such system.

IBM means to replace the white boxes they use now or build themselves like Google does.

It says it’s got a few hundred early adopters and potential customers in China, Germany, Japan, the UK and America, including Yahoo and Texas Tech, which is thinking of using it for a HPC center.

WinterGreen Research puts the market at $10 billion.

IBM calls the thing iDataPlex and leverages its blade server widgetry to build what it calls a “completely new design point.”

It’s supposed to more than doubles the number of systems that can run in a single rack – something like a 138% more servers on the same floor tiles at 20%-25% the cost – and promises 40% less power consumption while increasing the amount of computing that can be done by five times.

The system can run at room temperature without air conditioning using a so-called liquid cooling wall on the back.

Power costs, particularly in developing economies, are killing massively scaled-out data center operators, which IBM figures spend 10-30 times more on energy per square foot that the average office building, but that expense isn’t going to stop the exponential growth of such things.

IBM says iDataPlex, part of its Blue Cloud initiative, will be available in North America in June and globally by the end of the year.

Besides installing the equipment in-house IBM intends to rent out the massive widgetry at its Cloud Computing Centers in Dublin and the IBM Almaden Research Center in California.

It said start-ups such as virtual-worlds company Forterra Systems are accessing an iDataPlex system in the IBM High Performance On Demand Solutions (HiPODS) lab in San Jose to test their applications.

IBM is teaming with vendors such as Intel, QLogic, Avocent, Blade Network Technology, Devon IT, Force 10 Networks, and SMC Networks to create an iDataPlex ecosystem.

Blade Network Technologies, for example, built its new RackSwitch G8000 Ethernet switch, optimized for cost and efficient cooling, specifically for iDataPlex.

Besides Red Hat and SUSE,iDataPlex will also support the open source, scale-out cluster management solution xCat.

Ann Winblad, co-founder and a managing director of Hummer Winblad Venture Partners, an investor in enterprise Web 2.0 and Cloud Computing start-ups like Widgetbox, Sliderocket, Wavemaker, Elastra and Move Networks, figures iDataPlex will remove some of the inhibitors holding Web 2.0 back such as the amount of space and energy required to serve content to more and more end users.