Pretty sure that Real Madrid and Barcelona dont actually owe that much in taxes anyway. It's Atletico Madrid that owe loads.
They're about as healthy financially as we are according to Swiss Ramble:
http://swissramble.blogspot.com.au/2012/04/truth-about-debt-at-barcelona-and-real.html
The issue is the TV deal which pretty much every line of the above confirms is killing La Liga and funding their success (along with their massive profile / popularity).