Update on my side from this: I live overseas and have a difficult time obtaining some of the go-to protein products for vegetarians, such as protein bars (esp Clif Bar Builders with 20 g), seitan, and tempeh. I just got back from a trip to the US though and was able to easily get in 75-90 g of protein and 150-175 carbs a day on a 1200 calorie diet. I realize 150-175 is not Atkins levels, but it's still generally considered low carb. It takes some finagling but it's definitely possible.

I'm on Weight Watchers, which is low fat (in general) so I eat nuts and seeds in moderation, since they are high in PointsPlus because of their fat content. I do believe that they are very healthy and important, but I don't allow myself unlimited nuts and seeds, KWIM?

1 year vegan here, and don't eat low carbs!
We need a lot of them, but carbs from breads and pastas are not good. Try switching to fruit.
Too much protein puts a strain on the kidneys, we really don't need much protein at all. About 1/10 of our calories should be protein, 1/10 fat, and 4/5 carbs.

I've been tweaking my diet to be low-er carb (like 30g - 100g net carbs a day), but I can't really go high protein exactly (at least not while remaining vegan). I think for vegans/vegetarians, if you go low (or moderate?) carb, you automatically have to go higher fat... which isn't a bad thing. I did low carb before going vegetarian (now vegan), and even with lots lean protein it was very hard to go low fat.
Right now I eat a lot of soy protein, nuts (love PB2, defatted peanut butter), low carb veg and moderate carb veg.

I guess it's POSSIBLE to go vegan/really low carb/really high protein, but you'd also be super restricted in food options.

I've been a vegan for a year and have been steadily losing weight. At first I lost weight effortlessly and then around 230 I had to start calorie counting. I keep my protein up with a smoothie with protein powder for breakfast everyday. Vega is the best whole food vegan protein powder but it is a bit pricey. I usually use source of life which is also awesome but is made from soy protein.

I also eat a lot of beans, tofu and tons of veggies. I love being vegan! It has been one of the best decisions I have every made

Have you tried Spelt Pasta? it still contains carbohydrate, but spelt flour is far higher in protein than other types of flour. It is also very tasty, so you hardly notice a difference.

Also, you could try something like tahini as a dressing for salads.

You can also get protein-enriched pasta and bread, which lowers the glycemix index. (I started doing this recently b/c I'm teetering on the edge of diabetes.) I try to eat very little animal fat and lots of "good" carbs and lean protein -- basically the Dean Ornish plan.