Hop Shots are a concentrated form of hop oils, added to the kettle by the milliliter.

http://www.northernbrewer.com/documentation/hopshot.pdf

We'd need to allow ml as unit for hops, setup this new hop type, and figure out a good AA value for the hop shots that lines up with their table. The table reduces utilization with boil time, just like Tinseth and Rager do.

Hop Shots may not be the right name for us to use, since it appears to be their brand name. Hop Extract or Hop Oil might be better.

We analyzed their IBU table and it doesn't line up very well with Tinseth or Rager.

Did some more digging on this, the product is actually a CO2 hop extract from Hop Union, repackaged by Northern Brewer. The person at Northern Brewer I talked to was very nice, but had no clue where the IBU table they publish originated from.

Some info from Hop Union:
Expect 35% utilization over a 60 minute boil.
The AA value can vary anywhere from 45-65%, depending on the type of hops used. This information is normally not on the product label though, so 53 is a good guess.
The CO2 extract has a gravity of 0.85 - 1.1, so roughly speaking 1 milliliter and 1 gram are about equivalent.