Awesome!  Those are very encouraging results.  I am busily working on the Armory 0.92 release, but after that I will have some time to see if I can reproduce your results locally.   If so, I think you deserve a bounty!    I encourage anyone else subscribed to this thread to collaborate with roman.z and see if you can get his solution working and verify that it works.  I pay out once I can use the solution to move a 2MB file between two laptops reliably, as long as the performance is somewhat close to what you just described.

Overachiever's goal:  can you find the right cables to move data back and forth between a smartphone or tablet?  How difficult would it be to demonstrate that you get sufficient performance?  I like the idea of taking a tx on your phone to the safe-deposit box, plugging in a 2-way cable between the phone and computer, and letting them do their thing.  Or two smartphones -- one online one offline.  Granted, android dev is a little out of scope for this bounty, but if we can at least propose a feasible path to getting there and expect that its performance will be acceptable, I think this solution will be 110% complete!