I did this last night with a 1L soda bottle of my IPA that had way too much leftover trub to bother carbing with my carbonator cap.
I removed probably about 1/3 of the water by freezing (pulling it out and shaking it every 20 minutes once it started to form crystals) and then running it through a hop sock I had sitting around.
Once I'd carbed it up, the results were amazing. Tons of hop character comes through, and it still finishes nice and dry.
I pulled another 2+ litres from the keg tonight and used the same method to pull out about 1/8 (it's getting late, or I would've let it go longer. This time I used a sanitized Nalgene 7BBL pitchable yeast bottle into a 2L CO2 purged Erlenmeyer flask. It's yielded about 2L of deliciousness, which I will try to turn into ~1.8 using the same process/equipment tomorrow night.
The results are good enough that I'm thinking about brewing another batch just to use this process.
It's worth noting that it's a very fruity 7.3% IPA with a ton of late hops, very generous hop stand/whirlpool additions and pretty significant quantities of dry hopping. It's balanced and very good straight up, but definitely one that's a lot more about hop flavor than biting bitterness. I dont think that just any IPA would be a good canidate for something like this, but with the right one, it makes for a pretty cool beer.