Most of the current crop of DSLRs that happen to be able to capture video can only do mono audio – not stereo. Since audio is a big part of the video experience, you need to keep this in mind. Use of a field audio recorder (from Zoom, Tascam, Edirol, M-Audio and many others) is recommended for stereo audio capture. This requires extra steps when editing to import the audio and sync – then mute the audio that was captured with the video…

Stay away from AVCHD – too much compression. Stay away from hard disc drive based camcorders because of their known problems with vibration and high altitude – and data recovery issues when the drive crashes.

That leaves the HV30/HV40. These capture to miniDV tape. Your computer must have a firewire port – USB will not work; USB-to-firewire cable/converter/adapter things will not work. DV and HDV format video continues to be the professional’s choice – evidenced by the continued use of DV/HDV format in the Canon XH and XLH series, Sony HVR series and JVC GY-HM series camcorders… and the proprietary formats of the Sony HDCAM/XDCAM and Panasonic DVCPRO HD series camcorders.

The effect you are referring to is "depth of field". This is typically a prosumer and pro-grade camcorder capability available when shutter speed and manual focus are use in a specific manner – and the switch from one in focus to another subject is called racking. I can do that with my lowly Sony HDR-HC1 – easier to do with my HDR-FX1. The Canon DSLR should be able to do that with any lens capable of providing DoF. So should the HV30/HV40 (without an add-on) – some folks add a 35mm lens attachment to more easily get that effect, but since that camcorder family uses a focus thumbwheel rather than a focus ring, it might be challenging to not shake the camcorder when you are racking the focus.

The least expensive camcorder with a focus ring – with all your other requirements – is probably the Sony HVR-Z5. Maybe the Canon XHA1.