I have prepared a zip file of various hdri images, mostly based on gradients, but also including the "Multi-colored box" used in one of the above examples.  Anyone who would like to experiment with them, just drop me a line....either through a IM here, or by email....and I will email the zip file to you.
The zip file is ~480 Kb, if that makes any difference.

RosemaryR
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"This...this is magnificent!"
"Oh, yeah. Ooooo. Aaaaah. That's how it starts.
Then, later, there's ...running. And....screaming."