Is Verizon the exclusive carrier of the CDMA iPhone 4?

No, according to Verizon's COO, Verizon and Apple's contract is not exclusive like the original contract with AT&T was. Though the CDMA version of the Verizon iPhone 4 is currently only scheduled for availability on Verizon, the contract between Verizon and Apple doesn't prevent other CDMA carriers (i.e. Sprint) from making a deal with Apple to begin selling the CDMA iPhone as well.