An unlikely marriage is being pitched again. Fortune contributor Kevin Kelleher is suggesting that Microsoft (Nasdaq: MSFT) should acquire Netflix (Nasdaq: NFLX) .

We've heard this before. Ever since Netflix CEO Reed Hastings was brought on to the Microsoft board four years ago, analysts and shareholders have been suggesting that the two names should get together. I was one of the early cupids trying to give the companies a nudge four summers ago.

A lot has happened since then. But even though Netflix is a lot more expensive these days, the pairing makes even more sense now.

On bended knee
Kelleher's thesis reflects recent developments. Remember Monday's iCloud announcement from Apple (Nasdaq: AAPL)? Did you catch the suggestion two weeks ago from Greenlight Capital's David Einhorn that it's time for Steve Ballmer to step down?

Well, Kelleher sees acquiring Netflix as a two-fer. On one hand, it would give Microsoft some serious ammo -- and consumer street cred -- to take on iCloud's master plan for the Apple-i-zation of the masses. Kelleher also sees the visionary Hastings as an ideal co-CEO alongside Ballmer.

But we can't just join the two interlocking puzzle pieces together.

For starters, Netflix won't come cheap. Unlike many of the tech stocks that have been correcting sharply in recent weeks, Netflix hit an all-time high on Monday. It's is packing a market cap of $14 billion, and there's no reason for shareholders to punch out unless it's at a healthy premium. The company has also been an aggressive buyer of its own stock. There are now nearly 11% fewer shares outstanding than there were two years ago.  

The accolades for Netflix, meanwhile, keep coming. Citi's Mark Mahaney upgraded the stock last month, raising his price target from $245 to $300. Caris & Co.'s David Miller reiterated his bullish rating on the stock -- and his juicy $316 price target -- yesterday.

Unless Hastings thinks Netflix is somehow peaking, he's unlikely to cash out for anything less than $20 billion. Shareholders may not play along unless they get half of the nearly $50 billion on Microsoft's balance sheet.

Making dollars and sense
Microsoft's name is an easy one to toss into the rumor mill. The company is cash-rich, far-reaching, and hungry for growth. There aren't too many companies that would be willing to offer $8.5 billion for Skype, the way Mr. Softy recently did. It was open to paying $6.6 billion for aQuantive four years ago. And it was willing to pay even more than that in its failed bid to acquire Yahoo! (Nasdaq: YHOO) a year later.

Rumors have recently tied Microsoft to the purchase of Nokia (NYSE: NOK) or Research In Motion (Nasdaq: RIMM), but the last thing Microsoft needs is a fading giant. I realize that pet owners often have pets that resemble them, but this is ridiculous. Microsoft needs an acquisition that would shake things up and make Mr. Softy a growth stock again.

Netflix may be too small to materially affect the income statement in the near term, but right away one would see an expansion of valuation multiples for Microsoft solely because of Netflix's open-ended upside.

The waiting is the hardest part
When I suggested a Micro-flix hookup four years, it would have been easy. Netflix had 7 million subscribers and commanded a market cap of $1 billion. Now we're looking at a $14 billion company with 23.6 million global subscribers.

Netflix would boost Microsoft's profile in mobile operating systems, consumer entertainment, and the streaming of movies on video-game consoles. The company that flopped with the Kin and Zune would be a winner again in consumers' eyes.

Given Netflix's rich valuation, Microsoft may decide to wait for a pullback, but it would have snapped up Nokia or RIM if all it wanted was a discount.

"Buying Netflix and installing Hastings as co-CEO would position Microsoft to return to the center of the tech industry," Kelleher concludes.

He's right, but if Microsoft always did the right thing, it wouldn't be in this predicament, now, would it?