ionut19 :
There is, MSI big marshal. But do you really need 3 cards like that? I suggest 2 of then and use a gtx460 for PhysX if you want to invest that much in a PC meant for gaming.
About the standard tri sly bridge, nvidia has the option to enable sli without that bridge. If not, the cards might come with that bridge or you can ask gainward if they produce it for tri sli.. that's if a normal bridge is not enough(don't know if it is flexible or board stiff so can't advise properly).
Awesome overboard motherboard! But, no matter how you slice it, even with the Big-Bang Marshal, one of the 2.5 slot cards won't fit; whether you go with slots 1,3,7 (1 pushing against 3) or 1,5,7 (5 pushing on 7) the cards are too wide:
http://www.msi.com/product/mb/Big-Bang-Marshal--B3-.html#?div=Detail
Slots 2,4,6, and 8 are 1x bandwidth slots even though the slots facilitate a 16x-sized card.
The SLI bridge comes with motherboards that support it. It isn't generally bundled with the card the same way AMD cards include the Crossfire Interconnect. If the motherboard supports 3-way SLI the appropriate connectors will be in the box. The Big-Bang Marshal motherboard comes with a single SLI bridge indicating 2x SLI only.