Asynchronous BVH building and rendering

Currently rendering the heavy scene and got an idea: why not to make BVH building and rendering asynchronous?
For now BVH building and rendering are being done in sequential order and each state delays the other. What if the BVH for frame 1 will be being built, while the gpu is rendering frame 0? This may save a lot of time.
Is it possible? Any ideas?

To us, BVH takes a fraction of the time compared to the actual rendering, so it isnt much of a issue… How long do your BVH builds take? most of the time is loading images onto the GPU / loading the objects themselves onto the card, not the BVH itself at all.

On a current project, the image loading / syncronisation of objects, BVH all takes about 5 seconds… thats for about 1400 objects, and ~1 million faces, and about 800mb worth of image data.

For me image loading, syncronisation and bvh building takes nearly 25 seconds with the simplified scene on i7-920 OC to 3.7 GHz and SSD. BVH building itself takes nearly 10 seconds. There are hair, liquid sim, particles with dupli objects and displaced objects in my scene (yes, everything, that speeds down the preparing process), 1.8 million faces. 25 and even 10 seconds are not essential when rendering the static images, but for animation it’s too long.