It wouldn’t be unreasonable to think at some point there might be some integrated thing, Mindy Mount, CFO of Microsoft’s entertainment and devices division, reportedly said during Citigroup’s global technology conference. Such a device likely would be a smartphone version of Microsoft’s existing Zune digital music player, but Mount declined to comment specifically about future products.

She also declined to comment on the rumor that Microsoft is considering buying BlackBerry maker Research in Motion. She did, however, say Microsoft was pleased with its future outlook in the mobile market.

Her comments coincided with the release of a consumer survey yesterday that showed the iPhone was the best-selling mobile phone in the US during July.

Apple sold 220,000 iPhone units, or 1.8% percent of all US mobile-phones sold in July sales, according to market researcher iSuppli. More than 4.5 million iPhone will likely be sold for the rest of the year, iSuppli predicted. The iPhone went on sale on June 29.

While iSuppli has not collected historical information on this topic, it’s likely that the speed of the iPhone’s rise to competitive dominance in its segment is unprecedented in the history of the mobile-handset market, said iSuppli in its report.