A: 

Something like this would be very easy to create.

First create a button style:

  <Style x:Key="ZoomIncreaseDecreaseStyle" TargetType="{x:Type RepeatButton}">
    <Setter Property="OverridesDefaultStyle" Value="true" />
    <Setter Property="IsTabStop" Value="false" />
    <Setter Property="Focusable" Value="false" />
    <Setter Property="Template">
      <Setter.Value>
        <ControlTemplate TargetType="{x:Type RepeatButton}">
          <Grid>
            <Ellipse Stroke="Gray" x:Name="Ellipse">
              <Ellipse.Fill>
                <RadialGradientBrush ... />
              </Ellipse.Fill>
            </Ellipse>
            <ContentPresenter HorizontalAlignment="Center" VerticalAlignment="Center" />
          </Grid>
          <ControlTemplate.Trigger>
            <Trigger Property="IsMouseOver" Value="true">
              <Setter TargetName="Ellipse" Property="Fill">
                <RadialGradientBrush ... />
              </Setter>
            </Trigger>
          </ControlTemplate.Trigger>
        </ControlTemplate>
      </Setter.Value>
    </Setter>
  <Style>

Then modify the ControlTemplate in Blend (create copy), and add something like this around the <Grid>:

  <DockPanel>
    <RepeatButton
      DockPanel.Dock="Left"
      Command="{x:Stastic Slider.DecreaseLarge}"
      ControlTemplate="{StaticResource ZoomIncreaseDecreaseStyle}">
      <Path Data="{StaticResource MinusGeometry}" />
    </RepeatButton>
    <RepeatButton
      DockPanel.Dock="Right"
      Command="{x:Stastic Slider.IncreaseLarge}"
      ControlTemplate="{StaticResource ZoomIncreaseDecreaseStyle}">
      <Path Data="{StaticResource PlusGeometry}" />
    </RepeatButton>

    <Grid>
      ...

You can play with the button stroke color, gradient fill, and the + and - paths to get it the way you want it. I assume the actual Office 2007 buttons are copyrighted so you probably won't be able to copy them too closely without infringing. But this will give you something visually very similar.

Ray Burns