Looks like the 2008 Trailblazer will be ready in September.

"Production launch for the next-generation Chevrolet TrailBlazer and GMC Envoy has been pulled forward slightly to summer 2007, going on sale that September as 2008 models.

The 2008 TrailBlazer and Envoy use a version of the current platform with few major modifications, supplier sources told Inside Line. The SUVs are a bit larger with room for an optional third row of seats. Interiors are dramatically upgraded."