'Blurred' is a new launching soon HTML template by AVA Themes that features a fullscreen background slideshow. Its maybe a touch bloated for a launching soon template but it features a ton of neat elements (Twitter feed, newsletter signup) I'm sure you can reduce if needed.
If you are searching something different and out of the line, please check out Blurred – Responsive Under Construction Template. Blurred is a fully configurable and easy to use responsive under construction template with amazing background animation and a lot of other great features. It has been specifically designed to be easily customized and it’s created for creatives who want to make under construction page in few minutes.