I always scream as loud as you.
Fortunately, post iOS 4, there at least a couple of options.
I love Media Mix, which is a universal app where cross fading is its specialty.
Highly recommended.
Also "djay", which is also excellent.
But the iPad version is really expensive since it is a full fledged DJ app.
I only use the cross fade part and luckily, the iPhone version is only 99 cents.
I just run that on my iPad.
So, I have since stopped complaining but the function should be added natively.