Vista - EXCEL like grid

I'm trying to create an Avalon custom control simulating the Excel
grid. It should have to be able to handle 5000 rows by 300 columns of
data.

My first approach was overriding the OnRender method and drawing the
visible fields, but the performance decreases when adding scroll
support because I need to repaint my grid all the time.

Another way is having a Grid element with the visible rows and columns,
and removing and adding the corresponding rows and columns to simulate
scroll.

What do you think? What would be a good approach?

Thanks in advance.

Is it possible to implement a Grid that supports virtualization? Is
that the right way to solve my problem?

In that case, should I choose Grid and/or VirtualPanel as base classes?
Should I implement IScrollInfo in that class?

Where can I find some information or samples to help me understand how
to implement a solution to my problem taking advantage of what Avalon
offers.

Thanks.