Ruby doesn't scale?
Mock shock! Say it aint so!
Ok, really scalability is a relative thing. I've seen apps where going with a spring/hibernate framework couldn't scale.
But looking at SCALA? Sounds like someone wants to pick the language du jour.
Seriously, you want speed, simplicity and ability to do almost whatever you need, look at C. You want 'flexibility and OO' then consider Objective C. Considering that Cloud is the new buzzword and its reminiscent of leasing mainframe time back in the '70's and early '80's then going back to C may be just the next best thing!