I had considered making the inventory two rows but decided against it. The reason I decided against it is that the inventory was never ordered "correctly" in my eyes for the original interface. So I decided to make one row of 8 instead of one row of 1-4 and one of 5-8. Just didn't seem right the other way. Still in the process of working this out...
I have to say... I'm VERY glad to find that none of my mods caused the interface to fail with today's patch. Although I've been fielding UI support from tons of people in my guild all day... though I've come to expect this after a patch with UI files. Always seems to happen.