Homebrew Mobile Phone?

I have been doing some thinking lately, and more about a "Homebrew Mobile Phone". I look at the iPhone and Windows Mobile Devices, and I wonder how much it would take to get all the parts needed to make a mobile phone and load some software on it. Basically I think the hardest part is getting the Wireless Antenna to work with the Carrier Towers. It would be nice to have a SIM card reader or something for a laptop, or a small USB device that you could plug into your laptop (with SIM card in the USB) and turn your laptop into a cell phone. Or even just build your own cell phone like you can build your own computer right now, load whatever software you want, and have it work with the carriers you choose.

I know Google has Android that they are working on, open source OS for mobiles, but what about hardware. Some quick Google searches brings up a few results, but after digging into it some, it doesn’t look like the projects are actively getting worked on. The one problem is, when you try to get some open homebrew mobile, all the hardcores just want to use Linux. Well, I want to put whatever I want on it, not just Linux.

A cell phone is just hardware, software, and some extra stuff to get it to communicate with the towers, I wonder why it isn’t more widespread that there are homebrew projects going on. If you listen to Walt Mossbergs video on how we should have a more open phone hardware to carrier relationship, it is spot on. I do wish I had more hardware experience, beyond basic soldering, maybe I would go ahead and start this project.