My company has been using a standard image to deploy to any Macs new or old via target mode firewire. That has worked perfectly for many years but now that we’ve moved to the Retina MBP’s and the 1-way firewire adapters, it doesn’t seem like we can use that method any longer.

Is there a known workaround for this? Preferrably something that doesn’t require additional software suites like Casper. External HDD of some sort? External DVD?

Standard image is built via InstaDMG using 10.7 if it matters.