Wouldnt you be best off with digi scoping setup? So clamp a digital cam infront of your spotting scope eyepiece... alot of the spotting scopes you can buy video digi scoping kits for them now to hold the camera- the little cannon pocket still camera i have takes great HD video aswell, and its tiny to carry around...
YouTube - Digiscoping Made Easy
do you already have a spotting scope? already have a camera? or...?
For super long range stuff, you really need the good quality lenses and hence the spotting scope... i doubt any of those little camcorders are gonna be upto it with their standard little lenses, regardless of their zoom range ... There is shitloads of youtube stuff where you can see the results of digiscoping, just search "digi scoping" in you tube... great quality... and the full vortex skyline spotter including digi scope mounting kit goes for about $500...