I’ve shot extensively with both the XL2 and DVX100a. Overall the DVX is a better camera for my needs. It’s also an easier camera to travel with if you do much traveling. However, if you’re looking for a MiniDV camera, I would highly recommending purchasing the new Panasonic HVX200. Even if you just use it for a while for Mini DV (without P2 cards) you will have the option to go HD whenever you want.
The price point on the camera alone makes it a worthy purchase compared to the XL2.
Where did you hear/read the rumor regarding Premiere Pro v2 and its support of DVC Pro 50/HD?
Adobe has been very silent about any updates to their software.