HIS showcased what appears to be the highest factory overclocked HD 3870 card. This card works at 850MHz for the core and comes with 512MB of GDDR4 memory overclocked to 1190MHz (2380MHz effectively). Of course, this card comes with HIS's own watercooling design.
The card uses a watercooling design which is actually a single slot watercooler block, so running two or four of these cards in Crossfire shouldn't be a problem. HIS described this new watercooling as a successor to their IceQ cooling lineup, and it will come under the name IceQ Liquid. The showcased solution is working in Crossfire mode, and according to HIS, these two cards can even be overclocked a bit higher, depending on your watercooling system.
The card should be available sometime in May, but the price is still unknown. Expect it to be a bit more expensive than the most overclocked solution, since it features DDR4 memory and its own waterblock.