Ok So here's what I got...

Mh/$ GPU hardware acquisition cost converted to ASICs
In this scenario every one broke even on their hardware, then pocketed the profit and resold the old GPU rigs and immediately re-invested in ASICs

The average Mh/$ ratio for GPU is ~1.74
The average Mh/$ ratio for ASIC used here is 46 (because I felt like it)

~25 TH = ~$14.7 million invested in video cards.

IF that $14.7 Million was re-invested in ASICs at a 1:1 ratio

The new network Hash Rate would be 676 Th = 27x

*clearly I have not added Data for FPGAs-> ASICs
*Does not include new money invested or mining profits re-invested
*Does not account for GPU depreciation
*Not sure how power use/efficiency affects these numbers
*Data is from https://en.bitcoin.it/wiki/Mining_hardware_comparison

Just a thought: Maybe the money in switching from GPUs to ASIC is in power savings? In which case ASIC designers/buyers will eventually be just as obsessed with GH/J Ratio as we all were with GPUs