hmmm... not familiar with Radion cards, nor the monitor you are using for that matter, so I'll just try to make some general comments:
1. Get an nVidia card! They are far better supported.
2. Try plugging in a different monitor
3. Never seen a "TVStandard" of "Projector720p" before, perhaps try "HD720p" instead which is a common one
4. The log file seems to indicate that it is going through the mode validation process multiple times - never seen that before, so I don't know what it means.
5. It is rejecting almost all the modes it is attempting to validate but the driver doesn't make it clear where those modes are coming from, nor does it summarise the valid ones at the end, so this makes it difficult to interpret.
6. The monitor seems to confirm it can handle refresh rates between 58 and 75Hz, your xorg.conf file limits the range of acceptable modes to between 59 and 61Hz - so effectively only 60Hz modes. The monitor is also confirming that it can handle a 1280x768@60 mode.
7. I think we need to confirm where it is actually validating your modeline, because towards the end it clearly says it is selecting some other mode - so I'm assuming that it couldn't validate your modeline for some reason. To pick this out you need to rename the mode from "1280x768" to something else like "1280x768-Will" in the definition and when you select it later on in the xorg.conf file. Then we should be able to pick it out in the Xorg.0.log file and see why it isn't validating...
BTW - I checked your modeline, the screen metrics of 1624x757 at 60Hz does give a pixel clock of 73.78MHz, so that is right, but the size of the porches and syncs can be critical to a screen, which means you can tinker with a huge number of combinations which still give the right resolution and refresh rates, but some the screen will accept and others it will not...
Oh, also it seems to see your card twice on PCI BusID 1:0:0 and 1:0:1 - not sure why, and it seems to think the second one is a full display device rather than just a child device because it complains there is no "Device" section for it. Don't think this matters, just thought I would mention it....