I've built these types of kits before and they can be very daunting. Just saying it's "paper and glue" doesn't start to describe the level of care and patience required. Just the tracks alone are a nightmare - each individual link is actually three to four individual pieces that have to be cutout, trimmed and glued together. Now, take the number of links on a Panther and multiply it by four.... and that's just the tracks.
What I don't get is - look at the level of detail from the running chassis, to the drive train, individual stations and controls, turret interior and fittings.....
Why can't we find kits with this level of detail? Even the very high-end stuff still needs to be augmented with photoetched details, resin doo-dads, and machined barrels - and even then we rarely come close to this level of detail.
I think the coolest thing about these is that what you buy isn't a one-off model - it's a computer image of the model. You then run it through your color printer with some heavy paper and voila - you got a model. Mess up a part, want to do another? Just hit print again and there you go! If you know graphics programs (like Photoshop) you can even go in and adjust the markings, add mud and debris, change equipment, etc....
Here's a link for one company that makes cool kits: http://www.delta7studios.com/index.htm