1st at this time you do NOT edit the files as they come off the card in FCP, you can with PPro CS5. For FCP you transcode them.
While DVDSP cannot do BluRay, you can make HD approval BluRay with the new version of Compressor. You can also use Encore and Toast, but no serious BluRay authoring on a Mac at all.
Personally I would spend the money for the SDD on a faster Mac, for heavy graphic, transcoding, compressing and rendering I think a beefier system would be a better use of your bucks. Plus as the SDD price drops you can always add that in later, you cannot add in processors.
RAID system, yours in fine but it is a little dated, SAS cards offer faster speeds but more importantly they can be set up as RAID 5 to give you redundancy. But your setup will get the job done, so it is not a bad choice just wanted to point you to a better choice. But the eSata will you a lot for your buck.
There should be a new version of FCP out this summer and MacPros normally get updated in July/Aug, so if you need it now, get it now, if you can wait there will always be new systems. But the system you buy today will be just fine when the new ones come out. If you are going to start editing the Canon footage now, I say get the system now.
Cannot comment on the BMC, no history with it.