Ashley, I know exactly where you are coming from!!!! My baby (2 days younger than yours) also has never been one to simply drift off to sleep. We say, Evelyn doesn't *go* to sleep, she has to *be put* to sleep. At different stages in her life, this has involved nursing, bouncing on the ball, walking, dancing, in the wrap, out of the wrap, swing, stroller, carseat, catching her first sleepy signal, waiting until she is beyond tired, etc etc. I also have wondered if she almost needs to cry (in arms, of course) before sleeping. And, I have also been very very sad and frustrated, feeling that I am not meeting my baby's needs for sleep.
That said, I am not sure I am in a qualified position to give advice, but since I am having a better day today, I will share what I think.
First, please try not to be too hard on yourself about this. I do the same thing so I can totally sympathize, but I think we really have to try not to for our mental health as mamas which directly impacts our children! You are doing everything you can do. You are going above and beyond the call of duty to provide a safe, happy, and appropriate environment for sleep. She's just not taking you up on it! You are doing what you can to meet her needs and you are a great mama!
Also, give yourself a break on the "causing bad sleep associations" thing. Instead of thinking of it negatively, maybe look at the fact that she is very alert and interested in the world, and has a hard time stopping that interest for long enough to go to sleep. Realize that it may very well be a stage or phase. I am not sure that sleep is totally based on habits (if it is bad now, it will be bad forever). I think it might change as well as other things change developmentally, and be tied into other developmental steps. You might find this article from a mom who blogs interesting to learn more about 4-month-old developmentally-related sleep issues!http://moxie.blogs.com/askmoxie/2006...t_are_sle.html
(FWIW, my mom said that I as a baby was very similar in sleep habits to my daughter. Mostly not napping. She also felt sad, frustrated, etc. And, now I as an adult sleep very well and do not have negative associations with sleep at all!)
Finally, a couple observations on the needing to get cranky thing. I have noticed more crankiness if she is overtired or has what I think is a sleep deficit (really bad night the previous night, etc.). I have also found that sometimes I need to provide her with a stable, unchanging environment (in my arms or in the wrap) to get through that crankiness... Before I would just change positions, etc, the second she fussed. Now I wait a few minutes to see if she will settle and often she does... this works best for us in the wrap because I tuck her head in under the rail. She sometimes goes through a fuss when I do this, but hopefully then the cries turn into talking and cooing and get quieter and quieter and lead to sleep... but then sometimes she has that glint in her eye, and I think she will not go to sleep no matter what I do!
I could go on and on because I have thought a lot about this, too! But, I will stop for now except to say that on Sunday I am taking a class at the yoga studio called "Helping your baby fall asleep happy." If I learn anything new, I will share it!!!