I am correct about the XHG1 outputting 1920 x 1080 through SDI. It's also true for the XL H1 and the XL H1s. You can easily verify the specs on the Canon site. Remember that when you out put through SDI you are not compressing it to HDV. You are using a computer with a SDI capture card to capture live, uncompressed video.
I like the Sony EX1 as well but as you mentioned it cost about $2K more than $5,000. It also suffers from the same problem as the HVX in that you store video to memory cards...albiet not as expensive as P2 cards, its still an investment to be able to do lengthy gigs. In addition, the EX1 is a CMOS chip and is prone to rolling shutter issues like skew and wobble when there's lots of camera movement.
Again, the point is decide what type of gig you will do the most and get the camera that fills the bill. Don't expect any camera do be everything to everyone. That's why I own 3 different cameras.