I wasn't in the market for a new camcorder, but I bought the Panasonic TM700 a few months ago because of the glowing reviews (see Camcorderinfo.com). I shoot mostly green screen, and it was so much better than any of the others that I'd bought that I just bought a second one.
The progressive 60p format probably helps by eliminating the hassle of keying interlaced video, but perhaps the 3-chip CMOS sensors also help.
It, of course, has a mic input jack for clean sound, and lots of manual controls.
I got both of them cheap directly from Panasonic through Corporate Perks (search this forum for "Corporate Perks"). Buying directly from Panasonic insures and valid warranty - no gray market worries (at least for those of us in the US).
I haven't done this yet, but I am considering buying an inexpensive camera with HDMI out, and feeding the HDMI into a Matrox or Black Magic card for 4:4:4 capture. In theory, this should give me better chromakey than the 4:2:0 colorspace of HDV.
I will second the TM700. I just did a greenscreen job for a client, an election video, where the client is standing "in front of the danish parlament". It was my first real green-screen job and I was pretty amazed, what it could do.
4:2:0 is a lot better than the 4:1:1 of DV. I'm pretty sure that the live HDMI output from most camcorders is 4:2:2 which would be fine for green screen.