Currently, to modify the default appearance of the cells you can use the CellDecorationsNeeded event of RadVirtualGrid. The event args exposes a predefined set of properties that can be applied onto the cell. However, there is no text alignment.

Introduce a cell text alignment property in the event args similar to the CellTextAlignment of the RadVirtualGrid itself.

It should have similar behavior to the one in RadGridView https://docs.telerik.com/devtools/wpf/controls/radgridview/columns/column-groups

This component will have the goal to achieve fast operations when dealing with millions of records from a data source. This should be accomplished by decoupling the UI logic from data management operations like loading, filtering, sorting and grouping which should be delegated to the server. Since the grid will not have ItemsSource property, the developer will be responsible for managing the data to/from the server through a given events.

Official version of RadVirtualGrid is available from R3 2017 Release of UI for WPF.
Check what's new in R3 2017 here: 
http://www.telerik.com/support/whats-new/wpf/release-history/ui-for-wpf-r3-2017