Johan your comment really does show you are a webdeveloper

I agree with you as well. There is no way that google can possibly put the efforts towards checking my inclusions and css files to actually determine what my text color is.
Although the very predominant thinking is dont do it, I see to many examples of high ranking sites that dont even try to use a sneaky method, just plop on white on white text, and thats it. This is why in the last few days my opinion of what google is or is not checking has changed drastically.
With that said if you are after a high density term you can rest assured that somebody will complain and IF google takes the time to do any followup then you will enjoy a sit out. It is a bad practice, and what little it will do to help you is really not worth the penalties.
On the topic of a graphical splash page what I would suggest is do a mix using nesting so that you use images interlaced with text. I can show you an example of this, just send me a message through the site.