Though the Canon XL2 is not an HD camera, can the output of the finished product shot on the XL2 be converted into an HD signal. If not do they have FCP without the HD feature for a little bit less cost? All I see on the Apple website is the FCPHD.

FCP HD is actually FCP 4.5, the ".5" being the addition of being able to handle Panasonic's DVCPro HD codec.

There is no current version that won't handle a limited amount of HD.

Your DV footage can being exported as various types of HD from FCP HD.
Final Cut Pro HD (http://www.apple.com/finalcutpro/codecs.html)