“I have about 50 pairs of Nikes in my closet, and it seemed to me like I should be treated differently by Nike than a customer who has zero pairs,” he said.

The thought inspired Swinmurn to start RNKD, which is launching in beta today. Customers can create profiles and upload pictures of items of clothing they already own by snapping a picture and designating brands and where they bought each piece.

“The idea was to bridge the gap between consumers and brands by using what people already have in their closets,” Swinmurn said.

Users will be rewarded with badges and points for uploading photos, and will have the opportunity to win gift cards based on their participation. Swinmurn believes brands could use RNKD as a way to offer clothing at a discount to their most dedicated fans.

The emphasis is on the brand, rather than the store at which the apparel was purchased, which is how many other loyalty programs are designed.

Swinmurn, who left Zappos before it was sold to Amazon, also gained inspiration for RNKD after starting a small clothing line called Dethrone, which creates gear and clothing for practitioners of mixed martial arts. He said he sells 99 percent of the apparel to small shops. “We have no idea who walks into the shops and buys the product,” he said.

Swinmurn is hoping to tip the market on its head. Brands are already giving discounts on clothing at stores like Ross and T.J. Maxx, and on online flash sales sites like Gilt Groupe, ideeli and Rue La La. But those discounts aren’t being given to the biggest fans of the brands.

Instead, Swinmurn argues, discounts should go to consumers who deserve them.

RNKD is based in San Francisco, and is self-funded by Swinmurn, who has an engineering team of one.

“Apple is effectively building a recurring revenue stream, where iPhone users pay on average $200 year to stay current with the latest phone,” Munster wrote in a note to clients this morning. “While its true that iPhone 4 is a more significant feature upgrade compared to the 3GS, and we expect this upgrade rate to decline next year, Apple has in three years built brand loyalty in the phone market that compels users to upgrade to the latest version and wait in line for one to six hours to pick up their iPhone.”

And Apple (AAPL) is not the sole beneficiary of that loyalty. Its carrier partners, particularly those with iPhone-exclusivity deals, are benefiting as well, though the upside seems to decline with every new launch. Munster says 16 percent of the new U.S. iPhone buyers he surveyed this year were switching carriers to AT&T (T), down significantly from 28 percent last year. This suggests two things:

• Most people willing to leave another carrier specifically to get the iPhone have already done so.
• Apple needs another carrier partner in the U.S. to further maximize iPhone sales.

The latter point is, of course, obvious. As I’ve noted here before, adding a second U.S. carrier, like Verizon (VZ), would essentially double Apple’s addressable consumer base. As recently as last week, analysts were predicting such a move would spike iPhone sales by nine million in 2011. Given this and the new switcher metric Munster cited today, I think it’s pretty clear where we’re headed.

So, how many iPhones is the analyst calling for Apple to sell this weekend?

“While we think Apple will sell between 1.0m to 1.5m iPhones in the first three days (including preorders), the actual number is largely irrelevant,” Munster wrote. “Apple is tapping into the global consumer spending sweet spot, mobile, and as a result iPhone numbers are going higher in the coming years.”

Click on table to enlarge:

In an investment note issued this morning, Munster estimated that the company sold 750,000 iPhones over the weekend–25 percent fewer than the one million units of the iPhone 3G model Apple sold during the launch of that device last July, but 50 percent more than the 500,000 he originally predicted.

“The only true benchmark for judging the launch of the iPhone 3G S will be the time it takes Apple to sell 1 million units. Apple sold 1 million 1st generation iPhones in 74 days and 1 million iPhone 3G units in 3 days. We are uncertain whether or not Apple will announce the 1 millionth iPhone 3G S; regardless, we are increasingly confident in our 5 million iPhone unit estimate for the June 09 quarter following the price drop of the iPhone 3G from $199 to $99 in early June and the launch for the iPhone 3G S, where interest in the device surpassed our expectations.”

A few other points worth noting from Munster’s note. The analyst surveyed 256 customers at Apple (AAPL) stores in New York and Minneapolis over the weekend about their preferred OS, the size of the iPhone they were purchasing and the phones from which they were upgrading, among other things (see table below; click to enlarge). In the 256, he found a mix of 66 percent Mac users and 34 percent PC, similar to what he found last year (61 percent Mac, 39 percent PC).

Of those surveyed, 43 percent purchased the high-end 32-gigabyte iPhone 3GS, less than the 66 percent of buyers who purchased the 16GB iPhone 3G last year. And 56 percent were upgrading from an old iPhone–up from 38 percent last year. “We believe this shows Apple is developing brand loyalty not enjoyed by other mobile phone makers,” Munster notes.

“At the outset of the company’s iPhone initiative, one of Apple’s goals was to develop the kind of brand loyalty it has developed among Mac and iPod customers, and we believe they are succeeding thus far. As the footprint expands, and loyalty expands as well, Apple will increasingly enjoy a base of customers who regularly upgrade to the newest version of the mobile phones the company releases in what appears to be an annual cycle.”