Lisa, depending on what you're looking for, you might be better off getting a regular ol (non-Marketo speaking) designer (you may already be working with one who's familiar with your branding/identity) to create the templates in Photoshop (PSD). You can then hire any number of marketo geeks to transform it into a Marketo template or just follow these directions yourself:
Beyond Basic Templates: Advanced Landing Page Template Development
https://community.marketo.com/MarketoArticle?id=kA050000000L5L3&src=comm
