Glad to make you happy DJ.
As BaldHeadedDork pointed out, you might not be able to find this board in the retail channel right now because it's new (hey anything that supports PC1200 has GOT to be new!) but it should become available very shortly.
I believe this is the only board on the market right now that supports PC1200. Of course you could get an older Rambus board and manage to overclock your memory to PC1200 levels if you are lucky but very few people have managed to do this, the reason being that the RDRAM clock generator chips on the older motherboars creating a bottleneck. For instance, if you remember, the TH7-II motherboard was a great overclocker but usually not that great for overclocking the memory because it had clock generator chips rated for only 400Mhz and therefore you were really lucky if you managed to overclock your memory high.
What some people did to remedy this situation was to actually replace the clock generator chips on the TH7-II's by ripping them out and soldering new ones on.
Well, now the SI-7 is out and since it supports PC1200 RDRAM, it's got the RDRAM clock generator chips to support it (rated for at least 600Mhz). Mind you, there still isn't PC1200 RDRAM on the market right now that you can buy but you will be able to get PC1066 RDRAM and easily overclock it to PC1200 speed on that board. As you know, there isn't a standard for DDR over PC2700 either but you can buy PC3500 RAM from manufacturers like Corsair.
Of course if you wanted to hold on a little bit, you could wait for official PC1200 RDRAM to come out so you can overclock even further but then this time, if the RDRAM clock generator chips on this board is rated for only 600mhz, then that will be a bottleneck again.
But hey, if you want further info on this board, there is big thread on it here:
http://forum.oc-forums.com/vb/showthread.php?s=&threadid=126087