The board's very odd shape is weird, too. Dunno what it's from, but it ain't no proto and is not even related to FPGAs, devboards, or videogames by the looks of it. Oh yeah don't rule out that pieces of the PCB edges might be covered with electrical tape, like fingers for PCI/AGP/etc ports. The two mounting holes on the end and the board being quite long and narrow reminds me of a PC card. I don't see any other mounting holes which is highly suspicious. With a board this long you need them to prevent it flexing too much due to the length. Those holes would be used to attach one of those metal brackets you find on the ends of PC cards.
Measuring my clear Jaguar shell, the board is a little over 9cm (3.5" wide), which is the width of a PCI card.
Those two smaller QFPs are very very interesting to me- there's two of them and they appear to be identical. They both appear to have a similar complement of components around them, and there's waaay too many parts around them for them to be purely digital (i.e. RAM chips, etc) so that smells like some kind of ADC, DAC, or similar type thing. The SOICs above them just adds fuel to that fire.
I was looking at those smaller Quad Flat Packages earlier too. The one on the right seems to have some centered writing, and no logo. I had a look for manufacturers who brand(ed) their ICs like this, and came up with Techwell, a fabless semiconductor company who made mostly video decoding ICs between 1997 and 2010 when they were acquired by Intersil. Some of the printing on their packages looks really similar to those two smaller QFPs.
The 3 images on the left are the original and then enhanced versions from the latest Chameleon 'prototype', on the right is a resized Techwell IC.
The Techwell chip I resized, and an example video capture/DVR card with similar components to the 'prototype'. I couldn't find an exact match, in fact I had some mich better examples earlier when I looked, but it seems that the 10 to 15 year old cards are pretty similar to the mystery board.