Yes. This is now possible, but requires a little HTML/CSS skills.
Refer to the following article and screencast for more details:
Invoice and Sales Order Template Primer
If creating a custom template is a little to technical for you, we can create a customization for you. There is a one-time fee for this service. The cost depends on the complexity of the design you wish to implement. If you are interested in having us create a custom PDF invoice template, please contact us and we can provide a quotation. Please include a PDF attachment as a sample of what you want the customization to look like.