Ok, this one's easy with one trick. If you want to modify the links shown in the SharePoint MiniConsole (shown, for example, as the "Create Site" and "Add Link to Site" buttons in the Site Directory), just open the page you want and look for code like this:

<asp:Content ContentPlaceHolderId="PlaceHolderMiniConsole" runat="server">
	<SPSWC:MiniConsole runat="server">
	<SPSWC:SPSRepeatedControls id="RptControls" runat="server" HeaderHtml="" BeforeControlHtml="<td class='ms-toolbar' nowrap='true' ID='_spFocusHere'>"
	AfterControlHtml="</td>" SeparatorHtml="<td class=ms-separator>|</td>">
		<Template_Controls>
			<SPSWC:CreateSiteButton runat="server" class="ms-toolbar" id="TBBNewSTSSite" PermissionsString="ManageSubwebs, ManageLists" ShowImageAndText="false"/>
			<SPSWC:AddLinkToSiteButton runat="server" id="TBBNewListing" class="ms-toolbar" PermissionsString="AddListItems" ShowImageAndText="false"/>
		</Template_Controls>
	</SPSWC:SPSRepeatedControls>
  </SPSWC:MiniConsole>
</asp:Content>

and modify the <Template_Controls> tag. SharePoint comes with a number of predefined buttons (such as the <SPSWC:CreateSiteButton /> tag), but they all derive from the <Sharepoint:SPLinkButton class. So to create an arbitrary link in the MiniConsole, just add something like this:

    <Sharepoint:SPLinkButton runat="server" CssClass="ms-toolbar" id="TBBNewSTSSite2" NavigateUrl="here.aspx" 
			  Font-Underline="false" Text="my link" />

The trick is that in SharePoint Designer, the <Sharepoint:xxx /> tags aren't presented as options, but they work just fine.