I'd take it to the MS store in your area and have their techs look at. They've been very responsive for me. I'd also like you to explain how in the heck you tried booting it from USB. I've never heard anyone on this forum mention that you could do that. If that is a legitimate way to boot a Surface, then wouldn't that rule out a bad SSD? I'm going to Google right now "how do you boot a Surface from a USB device.
Well I guess you can boot from USB. Here is the steps right from Microsoft.
Start from a bootable USB device when Surface is off
Step 1: Attach a bootable USB device to the USB port.
Step 2: Press and hold the volume-down (–) rocker.
Step 3: Press and release the power button.
Step 4: When the Surface logo appears, release the volume rocker. Surface will start the software on your USB device.
I have to ask since you were smart enough to create a bootable image of your Surface, did you test it after you created it to see if you could boot from it?
From another thread I found it appears you are unable to boot when the SSD drive fails. You can't enter recovery mode. The techs offered 2 different methods to boot from the USB drive. They also mentioned a hard reset. This is done by holding down the power and the + volume for 15 seconds. Again from the other threads those that received the blue screen of death were able to resolve the issue booting from the USB. Unfortunately It doesn't appear my issue is actually software related.
In my case neither option would work.
The USB seems to work for those who actually have the software issue that was caused when the 8.1 update was released. The recovery file comes from Microsoft's Website. They offered this file as 1/1000 users according to their site experienced a specific error/blue screen after the install.
I'll do an update if I go ahead and replace the motherboard myself.