Turn off pagination — only on a custom archive?

Hi! I´m about to finish a theme (currently at 1979design.se w dummy content) where I have an issue I can´t solve.

‘Portfolio’ is built as an archive for my custom posts with template file archive-portfolio.php. This means I got alot for free when it comes to the loop – no need for special queries there.

Question: How do I turn off pagination only here? I know how to set up a query doing that, but I thought it would be nice to keep the loop intact, for once, when it comes to custom post types.

The big picture for ‘portfolio’: To use the left sidebar (the taxonomy items for portfolio custom post types) to make some nice jQuery fades to filter the portfolio-list. (Today only the ‘no-javascript’-fallback works, with links to the taxonomy.php templlate.

I´d love to get this work and I´m more than happy to share the final solution for ‘portfolio’ with template files and jQuery filtering!