The 20x zoom part will be the hardest one to find. To reduice the cost most seem to have 10x~12x optical zoom and give you a digital zoom.
Mini Dv is still the best way to go at this time.
Read some reviews on C-Net and the link below then go to a store and get your hands on them Sony, Canon, Panasonic, JVC are the best out there for the most part.

http://www.dvspot.com/
Has review of a JVC model with a 25x zoom check it out. John