Hi benandaim:
Well, I did do exactly what you are proposing, I went from a crappy Bogen head with my DVX-100a to a Sachtler DV-6SB with my HVX-200. I used to own a Sachtler Video 20 with my BVW betacam and have always regretted selling it but I needed to sell the package at the time. The DV-6SB is a miniature version of the Video 20, I love it. I have dragged it around in a lot of different situations and it never disappoints me.
I second the Sachtler. Like Dan I use to own a high end Sachtler (an 18P ) for use with big cameras. I sold it when I started using smaller cameras more. I shot on a Gitzo 1380 for the last couple of years , always missing the smooth silky reliability of the Sachtler. Within the past month I bought an DV8SB ( $2,100.00) and I'm back in Sachtler- hog heaven...
I don't care for Sachtler's legs , but their heads are worth every penny. Spend the money on a quality head.