Conversion of Zencart theme to HTML5

I have a plain Zencart theme that currently uses XHTML 1.0 Transitional and utilises Tables/Frames for layout elements. I wish to have this and all the components of the theme converted into HTML5, according to the following: W3C Valid HTML5 Commented HTML5/CSS Semantic & Clean Markup Search Engine Friendly Load Speed Optimization Clean & Valid CSS3 (Using LESS if possible) Descriptive Selectors Naming Resizable Fonts CSS Reset Must be cross-browser compliant, preferably using a flexible layout. Follow WCAG 2.0 (AA) and Section 508 accessibility rules. Also: Print-friendly css Implement Microformats Implement CSS Sprites (where possible) You must have experience writing SEO-Friendly websites