we have already invested more in undelivered BFL hardware than we currently have invested in the equipment currently running the network.
Unlikely. Current network hashrate is over 12 TH/s. More than 10 TH/s of this is probably due to GPUs.
That's roughly equivalent to ~33000 HD5830s who are the king of MH/$ of GPUs. So a lower bound on the $ invested in GPUs is currently $3.3 million USD.