Hi Defcon, I'm not sure I can help, but I will try.
Low carbing for weight loss:
From most of the mainstream low carb diets I have read, you want to replace your carbs with protein AND fat. Eating just protein is harder on the body - now for weight training, I know that can be a whole different ball game, and I'm not familiar with that. I do know if you add more fat to your diet you will add a good amount of calories, because fat has more calories per gram than protein does. Eggs, cheese, butter and creams would be a quick way to add that on. The basics of low carb diets usually say fat is your friend, and you will still lose weight if you have high fat, high protein.
Low carbing for muscle building:
I have looked at some ketogenic programs that are intense high protein low fat and carb, and I don't know much about it at all! My best suggestion is to go to the Body For Life forum and talk to some of the members. Body For Life isn't a low carb diet, but I think it does limit carbs. It is all about weight loss and increased muscle tone. You can visit the forum at Ladies and Gents Who Lift
http://www.3fatchicks.com/forum/foru...?s=&forumid=80
It is moderated by MrsJim, and she is awesome.