Ext JS 4's brand new grid supports infinite scrolling, which enables you to load any number of records into a grid without paging.
The new grid uses a virtualized scrolling system to handle potentially infinite data sets without any impact on client side performance.
This example illustrates loading of all the records up front and buffering the rendering. Take a look at the Forum example which illustrates dynamically loading data from a remote source.
The code is not minified, see buffer-grid.js