An idea: New Service Deal for Existing Service

[libra1980]

So the wireless companies have reminded us repeatedly that service is a means to an end. I have been with Sprint for a long time, and my contract is expired. I'd like to get a nice new phone (a super sexy one with a 2 mp camera), but the deals one can get for renewing his contract for an additional 2 years are not nearly as good as the deals one can get for signing up for new service (see amazon.com's wireless offerings, for example). So Sprint prefers new customers to old ones. No wonder, because I don't want to shop for a new plan; I just want a new phone. But here's my idea: since I'm on a family/share plan, I can drop one line from Sprint and come back, say a week later, as a new customer. Right? So either I can
1. sign a new contract with another carrier, porting my number to them, then cancel within the cancelation period, or
2. transfer my number to a hypothetical service (that may or may not currently exist) that would register my number without providing any service and not make me sign a contract (business idea?)

I'm interested in feedback about my two ideas and other ideas from people who have already solved this problem. What is the window of opportunity for cancelling new service, and what happens if I buy a phone with a new service discount and then cancel service?

Why should I pay more for being a faithful customer?