What I require is a portable device that can be constructed to contain two people which allows us to converse, but does not allow for anything electrical to work inside and doesn't allow recording/observation from outside.
I will pay any price for my privacy.
Can this be done?
There's a lot of question about the size and purpose of this device. If by "portable" you're envisioning something that will give you privacy in, say, an airport... no.
By using it you give yourself away.
Fundamentally the two requirements are in opposition. Actively suppressing surveillance and electronics is a privacy Catch 22. Using it reveals your presence.
There's the movie cliche of the hero shooting out the security camera. This is like that... except the guards aren't dumb. As soon as the camera goes blank they'll investigate. But it's far worse.
You turn on your device and what happens? The lights turn off around you. Security cameras pointed in your direction mysteriously go blank. The coffee machine stops working. Microphones and cameras, even in personal cell phones, stop working. This is going to draw a lot of attention from people nearby. Security and maintenance will notice the disruption and someone will come investigating.
For the real world version of this, watch How Governments Have Tried To Block Tor. Tor is a way to get private communications over any network. But using it suggests you have something to hide, so you'll have increased scrutiny. The government can even make its use a crime. So Tor has done its best to be indistinguishable from normal encrypted web traffic. The cat & mouse game between Tor and governments trying to detect Tor is the subject of that video. It will be enlightening how far this goes.
By using it you're committing computer crime.
You're probably committing multiple computer crimes by interfering in so many electronic devices you do not own. People in prison don't get a lot of privacy.
It can be defeated with a film camera.
A $5 disposable film camera can defeat your device. It has no electronics. It's purely mechanical and chemical. Maybe the flash won't work.
It can be defeated by eyeballs.
A couple agents watching you, or even just people nearby, will foil your device.
"I looked over when the lights suddenly went out around one table. I saw Mrs. Doe hand an envelope to Mr. Criminal and receive a package in return. Then two guys in suits walked up and arrested them."
If you can do that, why not just take over the world?
Your magical device needs to suppress observation from the outside. That means the cameras and microphones on everyone's cell phones, the security cameras across the street, the body cameras on police, and even the directional microphone pointed at you from a block away in the FBI van investigating your fishy activities.
If you use a blunt device such as an EMP, you're gonna be noticed. You'll need to know what observation devices are directed at you, intentionally or not, and target them all individually. Maybe you can knock out the cameras with carefully directed lasers, but you have to know they're there first and track them with precision. Microphones are going to be much harder to direct noise cancelling at.
Again, this doesn't seem practical and it's going to get you noticed.
If you can somehow "hack in" and edit yourself and your partner out of the image or audio... why are you messing around with this as a privacy device? You can control any electronic device around you! Take over the world!
Such a device harasses the people around you.
You'll pay any price for your privacy... including interfering with the lives of everyone around you by disrupting all their electronics and electricity. And if they have a pacemaker? Self-driving car suddenly goes dead? Traffic systems go dead? Oops.
Sure, you can do it, but it's morally bankrupt.
Passively, yes... sort of.
Meet somewhere isolated
No fancy tech necessary, just meet somewhere away from technology and people. Pick an isolated spot in a large national forest and meet there. If someone follows you you'll easily spot them because nobody should be out there; call off the meeting.
A small, quiet surveillance drone makes this more difficult, but that assumes you're already being actively tracked.
Act like a bank teller
@Vaesper and I had a chat about it and worked up a "practical" solution.
Use a van or small truck. Fit it with audio insulation and a Faraday cage to stop outside audio and electronic observation.
There are two doors, one for you and one for them. Their door has a strong electromagnet in the frame to wipe out and fry any magnetic storage. It also has a body scanner like in an airport. They're also searched by hand to make sure they don't have anything EMP hardened or hiding in its own Faraday cage. EMP hardened devices are larger than normal and easier to spot.
If you want to get extra paranoid, and they don't have to see your face, instead of one room there's two rooms separated by a solid wall so they can't see you. You can, of course, see them via a camera. In the wall is a speaking tube like on a ship to talk through. For passing items there's a drawer like a bank teller has.
While this is "practical" from a technological sense, such restrictions and paranoia will probably insult and drive off anyone wanting to do business with you.