Take a digital photo of a random room in the house and try to get the lighting/perspective right for use as the background. Blur or soften the digital photo a bit. Make a mask render. Use your favorite 2D graphics program and overlay this image on top the blurred photo using the masking. Make sure to postwork the translucent parts appropriately, since Bryce doesn't handle them too well when it generates masks (either all or nothing it seems.) I think it's a fairly simple idea for a background and it should work somewhat decent.

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Barbequed Pixels?

Your friendly neighborhood Wings3D nut.
Also feel free to browse my freebies at ShareCG.
There might be something worth downloading.