Transparency is impossible as soon as you have a two stages (source and compiled) code
No matter how you lock things (TPM, source review, etc..) the interaction between compiler (a
complicated compiled code) and source code cannot be ensured.
The only solution would be to write directly machine code by hand and have it audited by
independent people. But then you have the processor and its intruction set, etc..
IMHO, the traditionnal hand based process solves all the issues and is much cheaper and
infinitely more trustable.