To give you an idea of some of the options already available, for some consistency, create a new .tpl inside the skin1/customer/ folder and call it something like, mycustombox.tpl
open up your newly created file (mycustombox.tpl) and add this inside it...
Code:
{capture name=mycustomdialog}
I'm a dialog box!!
{/capture}
{include file="dialog.tpl" title="A Custom Dialog Box" content=$smarty.capture.mycustomdialog extra='width="100%"'}
<br />
{capture name=mycustommenu}
I'm a menu box!!
{/capture}
{ include file="menu.tpl" dingbats="xlogo.gif" menu_title="A Custom Menu Box" menu_content=$smarty.capture.mycustommenu cellpadding=$fc_cellpadding}
<br />
Then open up skin1/customer/home.tpl and locate one of the following TDs and place {include file="customer/mycustombox.tpl"} underneath them.
<td valign="top" width="100%">
(add include below this code for your main content)
<!-- central space -->
or
<td class="VertMenuLeftColumn">
(add include below this part for your left column)
or
<td class="VertMenuRightColumn">
(add include below this part for your right column)
If nothing shows up use cleanup.php to clean the cache.
Hope this helps.