You see, the main problem to Dry Ice/LN2 benching is condensation, it's a b*tch and will mess up your hardware. About a year ago I discovered DSI fluids and a product called Opticool. It's a di-electric oil that is pourable to about -90°C.
So I thought, hey, why not submerse a motherboard a couple inches under OIL? No foam, no saran wrap, nothing! So I picked up this great little resealable plastic tub. I placed the motherboard on spacers in the tub, elevating it about 1cm from the bottom just in case any water made it into the oil. I mounted the LN2 container, a massive 1000gram block of Copper and all miscellaneous cables and such.