Well I've been reading all this and had a couple ideas running through my head.
Basic Parts list:
Summit racing sealed battery box
http://store.summitracing.com/partdetail.asp?autofilter=1∂=SUM%2DG1231&N=700+115 &autoview=sku
RCI 1 gallon fuel cell
http://store.summitracing.com/partdetail.asp?autofilter=1∂=RCI%2D2010A&N=700+115 &autoview=sku
Johnson CM30 pump
http://autoperformanceengineering.com/html/jabsco.html

Various adapters/fittings/Lines

To address the first issue of isolating the coolant for the intercooler:

Mount battery box in trunk with hole drilled for ice vent/drain
Mount RCI fuel cell inside box attach lines and fittings run to engine bay and seal all holes in box
Replace crap stock pump with Johnson and route new lines accordingly
Est. about $400
On track days or whenever you could pack the box with some regular ice or perhaps a little dry ice. Even without the ice I'm sure the temps will be lower and the system will be more efficient having the coolant in the car, separate from engine coolant and with more capacity.
Could go one step further and replace the exchanger but it will be more costly and fitment could be a bit*h?
http://dagostinoracing.com/index.php...ducts_id=11828

Along the same lines you could mount another RCI cell in the box(looking at the dimensions should fit) for a water/alcohol injection system and super cool that with either form of ice.

Just my 2 cents on the subject. All in theory at this point.