Hello! My son was colicky for about 4 months (he's now 3 yo) and I was going crazy trying to figure out ways to calm him. I have a few ideas that might help, but it really sounds like you've already done your research and are trying everything you can. First, it's wonderful you're breastfeeding and don't let anyone tell you to switch to formula to alleviate the crying. Cow milk in my diet was largely responsible for my son's colic and it got somewhat better after I cut out ALL dairy. Read labels and don't eat foods that have casein or whey in them. Babies will suck in more air with a bottle so stick with breastfeeding even if your little one has a sensitivity to dairy in your diet. I tried burping my baby a few minutes into the feed and this helped a little. Burping earlier and often during a feeding gets the air bubbles out before they have a chance to travel further into the digestive tract. (oh, and like you, mylicon did very little...although I think my son was distracted from crying because of the sweet flavor!)
Have you tried white noise? The swish-swish of the dishwasher calmed my son. I have the silliest picture of him swaddled up and laying on the floor in front of the dishwasher sound asleep. Radio static, washing machine, bath water going. Conair sells a sound machine with white noise as an option on it for about $20. Putting my son on top of the dryer while it was running worked a few times.
Getting in the bath tub with my son worked a few times. Getting the warm water over his belly calmed the crying. Go ahead and nurse him right in there. A bit of a warning though, I was pooped on several times, but hey, my son wasn't crying anymore!
There is an online colic support group at colicsupport.com. Some folks at this group swear by probiotics. I hadn't heard of using probiotics until after the colic days were over. It may be something to look into.
Harvey Karp's Happiest Baby on the Block is a great book about calming fussy, colicky babies.
My second child, now almost 1, had bouts of inconsolable crying in his first 2-3 weeks of life. A sling was useful in calming him. I'd put him in the Baby K'tan (www.babyktan.com), turn up some white noise on the radio, and bounce him around or pace and he could go to sleep.
Having one calming method work for a little while and then not again is typical of colicky babies. Fortunately they just grow out of it when they're ready and all you can do in the mean time is keep trying new things. It sucks. It really does. But hang in there...it will get better.
All the best to you and congratulations on your new little girl!
J.