You could use ScaleTransform in RenderTransform on IsMouseOver. If you want the Scaling to be done from the Center of the Control you can use RenderTransformOrigin="0.5,0.5". Also, you'll probably need to set the ZIndex in the Trigger to make sure it is displayed on top of the other Controls. Example with a TextBlock
Update
Try it like this
<ItemsControl Margin="50">
<ItemsControl.Resources>
<Style x:Key="ScaleStyle" TargetType="TextBlock">
<Style.Triggers>
<Trigger Property="IsMouseOver" Value="True">
<Setter Property="Grid.ZIndex" Value="1"/>
<Setter Property="RenderTransform">
<Setter.Value>
<ScaleTransform ScaleX="1.1" ScaleY="1.1"/>
</Setter.Value>
</Setter>
</Trigger>
</Style.Triggers>
</Style>
</ItemsControl.Resources>
<TextBlock Style="{StaticResource ScaleStyle}" RenderTransformOrigin="0.5,0.5" Text="Something.." Background="Red" Height="20"/>
<TextBlock Style="{StaticResource ScaleStyle}" RenderTransformOrigin="0.5,0.5" Text="TextBlock2" Background="DarkBlue" Height="20"/>
<TextBlock Style="{StaticResource ScaleStyle}" RenderTransformOrigin="0.5,0.5" Text="TextBlock3" Background="DarkBlue" Height="20" Foreground="White"/>
<TextBlock Style="{StaticResource ScaleStyle}" RenderTransformOrigin="0.5,0.5" Text="TextBlock4" Background="DarkBlue" Height="20" Foreground="White"/>
</ItemsControl>