As TDC mentioned there were several other submissions.
I believe it might have also mentioned something along the lines of most of them being tracked or wheeled & in the 30t range.
So think Galleon, Hunter, Striker, Badger type vehicles.
But as mentioned, none of them were ever fluffed out & probably were prototypes.
I dug out my copy of 3026 and it says "Most established vehicle manufactures were submitting proposals costing about 800,000 C-bills."
Later it says under deployment
"Three weeks of grueling testing left just two machines under consideration: Lewis's machine and a 30-ton tracked vehicle from Defiance Industries."
This tells us some stuff but I am not sure what Defiance has produced especially in that range and motive type. It also doesn't limit the cost to the 800K price tag but we can assume it would be close to that.
The next sentence talks about how the final test was to be done with lasers on low power.
This doesn't necessarily mean that the vehicle had to have a laser but I would bet it did.
I do have to think that a company like Defiance wouldn't just eat the costs of prototyping a 30 ton tracked vehicle that was fairly competitive against a common scout Battlemech.
You would think their PR and advertising firms would have been able to find contracts given the tech regression of the time period and the want for any military equipment.
Maybe we will get hints to what this vehicle was in a future TRO or some other product.
I don't know why not knowing is sticking in my craw so much. I just want a complete BattleTech Universe.