I found the switch to remove/edit the guest welcome message fairly easy but have not been so lucky with the customer logged in welcome message.
I have searched all over and have found nothing. Would someone please point me in the right direction.
Thanks in advance...
From your question it is not clear that, whether you are using any custom theme for your website. However I have a strong feeling that, you are using a custom theme. In default rwd/default theme I dont think such welcome message does exist ! (May be I am wrong :)).
When a customer login into a page, he will taken to dashboard page. The action for this looks like customer/account/index. Layout handle corresponding to this action is customer_account_index. So any template comes under this layout handle is in hot spot. But the good starting point would be app/design/frontend/<your_package>/<your_theme>/customer/account/dashboard.phtml. I pointed out this template because, it is a kind of parent template for this action. This template constitutes dashboard content.
So my assumption is that, either this template holds that "welcome" message directly. Or it may hold that block which generates that welcome message as like this
<?php echo $this->getChildHtml('welcome_block_alias');
welcome_blocks_alias is a block which comes inside customer_account_index layout handle. (it comes as an as property of a block). So find that block and find out which template that holds by that block.(It will specify in template property ). Open that template and remove it.
So using this info, please dig more. You can definitely find it.
Note: You can find the layout handle customer_account_index inside customer.xml file at app/design/frontend/<your_package>/<your_theme>/layout/customer.xml
