Multiple templates for the same category, visitor can chose

Good day;

I am trying to achieve something similar to allowing your blog visitor to chose the theme, but within a single theme, and for a particular category.

I have a category featuring my work in graphics, I am showing the posts as a thumbnail (custom field) and title + excerpt + meta.

I would like to offer the possibility to my visitors to chose a “Gallery” view, where they will only see the Thumbnails floating next to each other.

I have searched and found nothing worth noting. I assume I will have to make use of sessions or cookies, and use it to load “category-regular.php” or “category-gallery” depending on the visitor’s choice.

Any hint to put me on the right track would be very very appreciated! ??

Best,
f.