There are many such lamps on eBay but they tend to be DMX controlled. You can get very small relatively cheap handheld DMX controllers but I suspect we're getting into the realms of overkill. I recently picked up nine RGB colour fading LED strips for GBP 190 which was a bit of a bargain. A simple par can should set you back about GBP 150 and somewhat less than that for a white one.

As for the patent, what a joke! PWM brightness control is in no way novel, I'm sure just within the group of empeg developers there is prior art going back decades. The very first program I wrote for a PIC did just that. The patent doesn't seem to have stopped many manufacturers around here - there are dozens of brands of LED lighting. Pulsar, just down the road from here, do little else these days - although I suppose it's possible they pay a license.

Rob