Much better
Maybe have the individual book blocks have an auto vertical scrollbar? Also probably you could move other formats to the right of the cover, as there is wasted space there.
I say if you need to modify the source, modify it. If you want your code merged into trunk, it needs to be as maintainable as possible, which means doing things the "right" way.
There are many people that run calibre from source, so you should still get feedback.