An IDC report issued last month ranked DDN as the largest private storage company by revenue. Of course, it helps DDN that 3PAR, Isilon and Compellent got scooped up in late 2010 acquisitions.

DDN CEO Alex Bouzari said he expects his company to remain private through 2011. Seven months ago as rumors swirled about DDN getting acquired, Bouzari told me the company was not for sale and he says that is still the case. Bouzari said DDN increased revenue 40% last year, driven by a growth in unstructured data across its core markets — media and entertainment, life sciences, high performance computing (HPC) and other verticals that require high bandwidth. He’s happy to stay on that growth track.

“We’re not pursuing M&A,” he said. “Our best opportunity is to scale up as an independent company.”

(Translation: it will take at least a 10-figure deal to buy DDN).

Bouzari doesn’t discount going public if the IPO market comes back as expected, but he doesn’t plan an IPO this year. Still, Bouzari is presenting at a Needham Growth Conference for investors today in New York, which isn’t something private companies usually do. Certainly not if they intend to stay private for long.

But to continue to grow, DDN needs to become more of an enterprise play, especially if it is to compete with EMC’s new “Big Data” tag team of Isilon and Atmos. DDN has its Web Object Scaler (WOS) object storage system to compete with Atmos, and Bouzari said it will add an enterprise NAS product late this year to challenge Isilon. The roadmap also calls for upgrades to two existing hardware platforms this year and the addition of enterprise software such as snapshots, deduplication, thin provisioning and replication to follow in late 2011 or 2012.

DDN has high-speed parallel file system storage for HPC and supercomputing, but no mainstream NAS. Bouzari said the NAS product will be a clustered offering that can scale up and scale out for customers who expect to have to add capacity and performance.

He’s also planning a refresh of DDN’s S2A6620 midrange and SFA10000 high-end product in 2011. He said the SFA10000 upgrade will boost that product’s IOPS and virtualization capabilities.

Still, it’s likely that when people talk about DataDirect Networks this year, it will be less about product upgrades than about M&A speculation.