I know the interest here is to drive the XM-L to spec @ 3amp, but I find the 2.8A AMC 7135 boards from shiningbeam to work flawlessly. Also they are much smaller and fit a wider variety of light sizes, from P60 style all the way up to mag mods. It does not push the XM-L to max output, but I don't think the extra 200 ma will make a noticeable difference to the human eye. They cost about the same as the DX driver, although, it is only rated to max 6V input which limits battery config to either a single rechargable lion, or maximum 5 x NiMh cells.
Either way, I'm always interested in new drivers too, so I look forward to ergotelis's test data.