I currently use an LG 29UM67 which is a 21:9 monitor which supports the features you are talking about. I was able to get it on Amazon for about 350USD and it supports upto 4 inputs simultaneously, either with different inputs or daisy chaining I believe.
Here is a link to LG's website for the same - http://www.lg.com/us/monitors/lg-29UM67-P-ultrawide-led-...
I have some potential options that may be helpful.
Option 1: Using an in-between hardware solution
One option would be Screens a product that resides between the screen itself and your inputs. It is in Kickstarter now but allows you to customize a good number of inputs by running its own internal software. Another option that is available now from my ...
I have a Bosch DLR165, which appears to have been produced around 2010. It's possible that I purchased mine that far back, or from eBay in later years. I found only one in today's eBay listing, but based on my experience with this one, I'd purchase a newer Bosch product with confidence.
The manual lists the maximum range at 50 meters, within your ...
To measure the signal integrity all you need is an oscilloscope. Your requirements aren't in the (old) I2C specifications, but need to be found in the data sheets for your particular devices connected to the bus.
For sniffing and analyzing the bus I'd recommend a Saleae Logic. (http://www.saleae.com). Later versions can perform analog measurements, too.
If it's acceptable to use a shoephone with it, the Pokit Meter looks handy. It and a phone (Apple iOS 10+, Android OS 5+ (Lollipop)) together would fit in your defined pocketspace, and it meets all other criteria, including an analog bandwidth of 500MHz.
A proper answer this time, since you seemed interested in my comments.
If you are up to it, AudioWeaver, the DSP code generation tool is free for ST Microelectronics microcontrollers.
How this works, is you create an effect/EQ/what you want in AudioWeaver and upload it to the memory integrated in the microcontroller. It then functions as a sound card. ...
What you need is called a demodulator. Due to the digital switchover, they are becoming more and more difficult to find, but can still be found if you know what to look for. It is essentially an NTSC TV tuner, sometimes with only a channel 3/4 tuner, that outputs some other standard output signal such as VGA, composite, Y-Pr-Pb, etc. Such devices used to ...
This is a monitor/TV that supports 4 HDMI inputs. It can display a single input or all of them simultaneously.
It has multiple layout options and comes with a remote. There is a video where you can see this feature in action.
It has been extensively reviewed:
Linus Tech Tips