You DO NOT NEED pci-x for SD SDI card
You DO NOT NEED raid for uncompressed 10 bit work (sata drives are about 30MB/s on slow and it is enough for 10bit 4:2:2)
You DO NOT NEED a new deck if you are willing to do the conversion in software – I don’t know about PC but mac even captures from firewire to 10 bit in realtime
Make Your investments where it counts and don’t belive everithing you read
-Kaspar