This is so many kinds of wrong...

The Qualcomm chipset that's used in the EVO is certainly the same CDMA2000/EVDO chipset that's used in the Nexus One. Qualcomm doesn't make WiMAX modems at all, you have to get those from Beceem, Sequans, GCT, Runcomm, Intel, or somebody else. The WiMAX chip in the EVO is certainly a separate chip just like the WiFi chip is a separate chip. It might share an *antenna* with the WiFi radio (since wifi @ 2.4GHz is pretty close to WiMAX @2.5 GHz) but it's not part of the cellular subsystem on the device.

So, you've got 4 radios in the device: WiFi, Bluetooth, CDMA2000/EVDO, and WiMAX. They all work independently.

Sprint has stated you'll be able to use WiMAX data and CDMA2000/EVDO at the same time on the EVO, which makes perfect sense given that the cellular radio can be active at the same time as the WiMAX radio is, because they are separate subsystems in the phone. WiMAX isn't that different from WiFi from the device's standpoint.

First, 700MHz isn't the magic bullet. You get longer range and better penetration, but the cell can still only serve ~200 or whatever active data users at a time. And if that cell is in a populated area, you have to build more cells (to serve the same number of people with good quality) and dial down the power of each cell (to avoid interference with the other cells). You don't want a cell that can only serve 200 people with a radius of a mile in NYC. So the longer reach of 700MHz only helps you in less dense areas, which aren't going to get 4G for a while anyway.

I'm pretty sure T-mobile didn't buy any 700Mhz spectrum in the 2008 auction.

Wrong, AT&T bought $6.6 billion worth of 700MHz spectrum to combine with the $2 billion they bought from Aloha partners before the auction. They've got a bunch too, but not as much as Verizon. But given that they still have a ton of 3G buildout to do, they probably aren't interested in building out LTE for a while.

Even LTE won't be 1GBit/s. That has to wait for LTE-Advanced and (for WiMAX) 802.16m. LTE tops out at 375MBit/s in a 4x4 MIMO 20x20 paired spectrum configuration, which nobody will be deploying for a long time.