I ordered a Brooklyn RGB cable yesterday because it was just 9 euros. And I read some reviews stating the cable delivers quite good quality.
And yeah, my cube has a digital out too (I bought one on the very first day) and I know that PAL games do not support progressive scan but at least 60hz mode.
By the way: I do not know where this comes from, but you definetly do not need a RGB cable to use 60hz mode.