Presuming the lighting is decent during the recitals then a Canon HV40. If we can have no such assurance, then a camcorder with larger lenses and imaging chips. You have found the standard def models (Canon XL2, Panasonic AG-DVX100, and Sony DSR 250).
Note that the Canon, Sony and JVC pro lines have no AVCHD compression models. I have not seen any real pros using the Panasonic AVCHD "pro" models. They generally gravitate to the AG-HVX200.
In the cases of the AG-HVX200 and Sony HVR-Z7U, they use P2 cards and compact flash, respectively, and record to DV/HDV/ and their respective company's DVCPROHD and DVCAM/HDCAM formats - not AVCHD. Note the lack of internal hard drive pro systems - if required, an external FireStore (or Sony) hard drive can be used with miniDV tape based camcorders - recording DV/HDV format.
I use XLR adapters on my Sony HDR-HC1 and HDR-FX1. I have a juicedLink CX231 and BeachTek DXA-6. Under low-audio conditions, the CX-231 has a better "sound floor". The example audio at juicedLink.com is accurate, but I have no comparison to the DXA-6HD. The preamps in the CX231 are a lot larger than those in any camcorder (and the DXA-6 - I do not know enough about the DXA-6HD to comment.
The pedigree on Br
I have no experience with camcorders and am looking to purchase one to record classical piano recitals. The camera will usually be mounted on a tripod and given minimal attention during recording.
I already have two external mics (Br