Harry Ruda, the guy who sold Softricity, the application virtualization start-up, to Microsoft two years ago, is now flogging the virtualized desktop-as-a-service, DaaS so-called, a logical extension to Softricity when you stop and think about it.

His new venture, Desktone, is ambitious. It means to have carriers like Verizon, whose traditional communications services are increasingly in jeopardy, and tier one computer companies like IBM use their infrastructure to deliver the outsourced service as service providers to large desktop populations.

Desktone will have a revenue-sharing arrangement with the service providers.

Naturally it’s supposed to eliminate the complexity of VDI and eradicate the barriers to adoption. The enterprise doesn’t have to build or deploy anything; it just has to sign up. And the service provider gets to turn a profit on its data center.

When exactly any of this will go live depends on ironing out some existing bugs. Maybe by the end of the year. And we’ll have to see what the latency is like.

Desktone calls its scalable hosted subscription-based platform Virtual-D and expects the service to run $60-$80 a month per desktop, a savings of anywhere from $300-$800 a year, Ruda calculates, depending on a company’s TCO, and cheaper than if you did it yourself.

It’s got Merrill Lynch using it sans service provider and Merrill says Desktone’s open architecture will let it swap the best-in-class virtualization technologies as they become available.

It could be Xen, XenSource, VMware ESX or Microsoft’s Hyper-V.

Desktone has also tied up with Wyse for low-power thin clients, promising users meaningful cuts in CAPEX and OPEX. Rich or repurposed clients can also be used.

The way Virtual-D works, the enterprise is supposed to be able to manage the virtual desktop environment – via a web-based interface – supported by the physical resources owned and maintained by a third party that reside either locally or with the service provider.

The enterprise can do virtual resource management, virtual desktop administration and template lifecycle management. It’s also supposed to be able to continue to use whatever operating systems, best practices, help desk and security policies it used before.

Well, as long as the operating system is XP – for now at least.

The applications are streaming via Microsoft’s RDP or Citrix’ ICA protocol.

Virtual-D kicks in an Access Fabric, a set of distributed services that links the authorized users to their virtual desktops.

This DNS-like Access Fabric is supposed to be “unique,” described by Desktone as an intelligent system that automatically delivers best-fit desktops according to user entitlements, policies, access location and available resources.

Desktone also provides a self-service policy-based portal accessible from a browser where users go to access their virtual desktops, manage them or create new ones without relying on IT. It is supposed to help with troubleshooting and requests for additional resources.

At the service provider end are the racks of hardware and software that form the building blocks of a virtual desktop utility grid that can scale to carrier-class size.

Desktone calls them “Elements” and provides a “Service Manager” or framework that ties the Elements into a grid. The Service Manager creates a loosely coupled “federation” of Elements, it says, manages pool across the Elements and collects data on Element status.

It promises to integrate all the virtualization layers including storage, applications, client devices, servers, processing and network technologies under a single management console.

Service providers can build Virtual-D Elements themselves using Desktone’s blueprints or get them pre-fabricated from Desktone partners.

After a $1.5 million angel round, Desktone, which was started in 2006 by Eric Pulier, who also started SOA Software, US Interactive and IVT, picked up $17 million in first-round funding about a year ago from Highland Capital Partners, SoftBank Capital, Citrix Systems and the China-based Tangee International.

SoftBank as well as Deutsche Telekom could become service providers.

Ruda says the brains behind the technology is Paul Gaffney, the former CIO of Staples. The company has maybe 40 people, more than half of them in Shanghai doing development, which explains Tangee’s involvement.