I think the current economics of baseball make one thing abundantly clear: when you've identified a young talent able to succeed on the MLB level, you have to sign him for as long as possible.

1) With free agent salaries spiraling upward, every non-backloaded deal looks like a steal. Albert Pujols (signed 2004) will make $16 million every year until 2011. It's not chump change, but if he was a free agent today, he could come close to doubling that figure.
C.C. Sabathia (signed 2005) is going to make $9 million dollars next season. Carl Pavano will make more than the reigning Cy Young winner.

2) Delaying free agency means more peak years playing for the team that paid to develop the talent. A hitter's prime years run roughly 27-32. Because of the 5 year service rule, most hitters don't reach free agency until they are 29 or 30 years old.
Overpaying the early years allows a club to have a couple more of those prime years before making a decision about whether to keep the guy or letting him walk.

3) Go over to Cot's and check out the pre-free agency contracts of Reyes and Wright, Grady Sizemore, and Jimmy Rollins.
No no-trade clauses.
I used to be indifferent to the NTC, but the last couple of years have reversed my thinking. I'll happily throw an extra couple million dollars to the player to keep control of his movability. If he gets hurt, is unproductive, or if someone better comes along, being able to trade the player to fill a need or acquire prospects is a huge plus in my book.
Even the biggest pre-FA signings (Pujols, Utley, and Santana) didn't include full NTCs. Pujols and Utley have partial NTCs, and Santana's partial NTC didn't become a full NTC until he finished in the top 3 in Cy Young voting the next year.

Cano wants a deal.

The best comparison is probably the Phillies and Chase Utley. Utley signed a 7-year $85 million dollar deal with a partial NTC last January. Comparing Utley's '05-'06 to Cano's '06-'07, Utley put better numbers (.301/.377/.533 vs. .322/.349/.504).
But Utley did it during his 26 and 27 year-old seasons. Cano just turned 25 last October. I think the difference in age would justify the larger salary.

There's also the New York factor to consider. Looking around the clubhouse, Damon and Matsui are making 13 million per year. Jorge's new deal puts him at 13.1. Rivera is making 15.
If I'm Cano I don't play for less than Johnny Damon, at least on average.

I'd guess a 5 year deal (buying 2 years of free agency, through age 29) averaging $14 million dollars a year, though likely back loaded so he makes $17 or $18 million in 2011 and 2012.

Somebody get Cashman on the phone.