It seems you forgot the most important part: your service :)
The UI presents your service, and the scaled out servers power your service, but without the service, all you have are some pretty pictures and a bunch of hardware.
Also, scaling is not a solved problem in the general sense. You have to find ways to elegantly and efficiently solve _your_ problems specifically. I say with confidence that if you aren't willing to be very involved in the scale out of your service, you'll likely design a service that won't scale out.
(For an example of an elegant tool used in scale out, see Facebook's thrift.)
Also, if service agnostic scale out is a small problem for you to solve, I encourage you to get rich by solving it. I'll buy your solution if it works.
The UI presents your service, and the scaled out servers power your service, but without the service, all you have are some pretty pictures and a bunch of hardware.
Also, scaling is not a solved problem in the general sense. You have to find ways to elegantly and efficiently solve _your_ problems specifically. I say with confidence that if you aren't willing to be very involved in the scale out of your service, you'll likely design a service that won't scale out.
(For an example of an elegant tool used in scale out, see Facebook's thrift.)
Also, if service agnostic scale out is a small problem for you to solve, I encourage you to get rich by solving it. I'll buy your solution if it works.