I'm also looking into the wireless STB's. I need to change the position of my TV and there is no TV outlet there. Off course you can call somebody to run a new cable. But I prefer to use those bucks to buy technology. So I'm exploring three options:

First option (cheaper) buy a TV transmitter & receiver. there are a few from $50-250 (TERK, Altech, X10). Cons: I didn't want to take the chance of adding more wireless signal in my environment (5.8GHz phones, 2.4GHz wi-Fi). So I didn't try it. they include IR repearters in order to control the STB remotely. i don't know which one would work with the Motorola VIP1200 and 1216 STBs.

Second option (most expensive): use a media receiver (XBox, PS3, DLINK DSM-750). These add the possibility to access your other media  through XP or Vista media centers. I selected the DSM-750. I'm not interested in gamming. It is silent and wireless. It works Ok to access my media. In order to access the STB you need a TV tuner. here comes the first problem. In order to access a TV tuner from these devices you need to use Windows Vista Media center. It doesn't work with XP Media center. On the other hand, my TV tuner doesn't work with Vista and I don't have Vista on any of my PCs. I'll update on later on. I was able to access some online internet channels using PlayOn Media center on my XP laptop. In order to avoid network problems I'm using a dual N router. My TV tuner would require an IR blaster to be able to control remotely the STB. The one I bought (next generation remote control extender) doesn't work with the UVERSE STBs.

 Third option: buy a a wireless access point or a wireless bridge. I still need to further explore this option. But the STB can get the TV signal from the network port (It works with wired LAN). Now all you need to add is a Wi-Fi receiver to communicate your STB to the network. PROS: No IR blaster needed. CONS: may use too much badwidth on the LAN and WLAN. I don't know.