In my project, I use ScrollViewer to show some long height infomation.
I use like this:
If it just a text, you could use this custom control: scrollable textblock. Otherwise, divide your content into blocks with size < 2048.
UPD:
2048px is a limit for GPU cached graphics. You can use a lot of controls (< 2048) inside a scrollviewer (total > 2048). In some cases all is fine, but in some it doesn't
For example:
In this case blue rectangle cropped at 2048px, but two rectangles with 2000px height placed one above the other looks fine.
The second example uses StackPanel to show 4000px area and it works too