Hi,
Though I’m not sure what kind of layout you want exactly, I think it’s impossible to move matrix horizontally at this point.
But making the mapping for MPD26 itself is not so difficult. 
I made the test map for MPD26 by editing the driver’s MPD24 files.
But since I don’t have MPD26 actually, please try to test it yourself.
Although I referred to MPD26 editor, assignment of some parameters may be wrong.
Download and unzip this file, and put the “MPD26” folder to;
C:\Documents and Settings\YourName\Application Data\Renoise\V2.6.1\Scripts\Tools\com.renoise.Duplex.xrnx\Duplex\Controllers
Also please refer this post too :[How To Start Editing Duplex Files]
[EDIT]
I bought MPD26 and made config file for it.
Please see this post