With the amount of modders, hackers, programmers I'm surprised no one has cracked open an iphone and switched the gsm for cdma chip and gotten some kind of working phone.
It's not even close to being that easy. The iPhone is a GSM phone from the chips to the software. Even if you did rip out the whole GSM RF section and soldered on a CDMA MSM chipset, the software won't know what to make of it. Instead of IMEIs, IMSIs, MSIDs and SIMs, it will see ESNs, MINs, PRLs and SIDs. Verizon's network speaks an entirely different language. The Phone preferences for things like enabling Caller ID, getting status on call waiting, and even conference calling won't work, because the access codes are completely different, or don't exist at all. Even the procedures for merely setting up a call or sending an SMS are different.
You'd have to redesign the whole thing, AND rewrite the OS to accommodate CDMA ANSI mappings. Not exactly something you can do with a simple jailbreak.
I'm not saying it's impossible to
ever have an iPhone on Verizon, but it will have to be done by Apple, and not by modding an existing model. Blackberry and Palm make similar model phones for the two networks, but that's because they write specific OS revisions for each product on each carrier, that knows what it's supposed to do with the differing hardware. Apple would have to do the same.
You'll also note that not everyone can pull it off. Palm is notorious for making CDMA smartphones that crash way more often than their GSM counterparts. My old Treo 650 on Sprint (and later the 700p) loved to crash and spontaneously reboot for simple things, like receiving a call, or just sitting there and getting handed off to another cell site.