Ok - tried printing a target from CS4 with the plugin and it worked perfectly with the new driver - The color looks all screwy in the proof preview on screen, but it prints perfectly.
Printing with Application Manages Color both PS and LR properly defaults to ColorSync (grayed out) in the Color Matching dialog and in the Main/Color it defaults to No Correction.
With Indesign choosing Vendor Matching in the Color Matching dialog and then in Main choose Fast Graphic Process and Color set to No Correction.
All color output using the old printing path with Indesign or the new printing path with PSCS4 and LR looks correct and matches. And printing unmanaged profile target from both printing paths were identical, at least to my trained eye. I did not measure them though.
Turning off CM in the PSCS4 print dialog works correctly for printing profile targets. The driver correctly defaults to ColorSync and in the Main window default to No Correction.
With these new Canon driver it all seems to work perfectly.
Ok I am not sure what is going on - maybee its the difference between the X000 and X1000 series drivers. I do see the behaviour you are talking about whereby Colorsync is not greyed out the first time you open up the print settings dialogue, and then subsequently greyed out on opening a second time - however, if I print with it greyed out as you are doing and select the profile in LR then I got bad screwed up prints (see my edit below about this as I fixed this issue). If I select the profile in LR and select color sync in the dialogue and choose the same profile (in my original workflow as outlined above) then I get correct prints. (See my edit below this issue resolved).
Of further interest is that I also see the opposite behaviour of what you note whereby if I select Managed by Printer in the color management section of LR and then open the Print settings dialogue Color Sync is selected and greyed out. If I select the profile in the color management section of LR and then open the Print Settings dialogue Vendor matching is selected and greyed out. The opposite of what you are seeing.
The way I see it is the print driver does not remember what profile or what setting is currently selected in LR's color management section when you first open the print module because I can induce the opposite behaviour (the same as you are describing) by exiting the print module with 'managed by printer' in LR's color management section.
Therefore I think the bug is that on first opening the print module the print settings dialogue does not see whatever you last had set in the color management dialogue in LR? (hence the reason the first time you open the print settings dialogue on coming into the print module nothing is greyed out).
Can you test at your end and see if you get the same results? (BTW: THis is all in 64 bit mode in LR - not 32).
Edit - sorry this post is getting long.. but I solved the reason I was getting screwed up prints if I printed with the profile correctly selected in LR's color management window and color sync selected but greyed out in the print settings dialogue - somehow my printer had been removed from the color sync utility. Re-installing the printer added it back in and now the prints are perfect - same results you are getting with the same workflow.
Still doesnt solve part two of the equation though.. the reason the first time the print settings dialogue is opened nothing is greyed out as noted above.