Hmmm, I'm not sure what you mean that they now have backpack ones. They only have the foot launch one's like the one I have and they they also have one's that you can attach a trike to it. Which you can also do with the one that I have. Those require a longer strip to take off and land.
Prices for a motor (backpack as you call it) and wing can range between $6000.00 to about $10,000.00. If you want a trike figure about another $2000.00 to $6000.00.
Training is the most important and critical component. That ranges between $700.00 to $1500.00. HOWEVER, there is one instructor out there that will train you for free. He even comes to you. All you have to do is get him a plane ticket. And if he can stay at your house, then that's even better. He's the best out there and is the one that trained me and a whole bunch of others. If you are interested, email me your info and I'll give you more information.
This is the best sport ever! The feeling of flying free like a bird is indescribable!!! You can fly as low as you want or as high as you want but I would stay below 15000 if you don't take oxygen! LOL
The sport is growing like a weed here in the US and it's the safest sport above ground.
Here I am flying low over the beach. It's incredible all the marine life you can see from up there.

Here I'm getting to lauch from an Airport but you can lauch from just about any open location.

And here is how I carry it around. The wing folds up and is inside the car. Most units can be taken apart within 5 minutes and fit in just about any midsize trunck. I just got a hitch on my car and bought a carrier for it. And you won't believe the crazy looks I get. Everyone looks!!!!

Take care,
Frank