I admire your perserverence honestly. I know a good friend of mine that was in her sons room day in an day out to get naps and I don't know how you guys do that. I am envious.
About the dark room. We had just darkening curtains, that didn't seem like enough so I put tin foil all over the windows (4 yes 4 floor to ceiling windows in his room lol) AND closed the curtains. It was like a cave day and night - it was great. He started to sleep but I think that was a combination of taking the paci, swaddle, getting on easy, dark room, white noise and using pat/shh and pupd to teach sleep. BUT why am I telling you this - because, a few months later at hmm.. 6m - I tried to slowly remove said tin foil allowing the room to be brighter and he started short napping - I put it all back and it stopped. Co-incedence? Perhaps but my son is 11m old now and I have no plans to remove it anytime soon LOL. So, I'm not saying making the room super dark and going to solve everything, but it can't hurt.
Also, white noise. I can't sleep without a fan on high facing the wall. I do the same for Owen - I think that helps too - having a constant sound that muffles house noises so when/if they DO wake at the 30, 45m mark they aren't disturbed by any noises that may be happening. Some people have babies that could sleep through anything - mine is touchy and the more white noise in his room the better lol.
I am sure you are doing these things, but I thought I'd toss am out there anyhow. I read some of your posts saying he is happy most often after a 45m nap. There was a month or so that all I had were 4 or 5, 45m naps lol. I just went with it because I tried TONS of things and nothing seemed to help. I failed miserably at w2s. I think it has to do with developmental stuff really. So, I knew he couldn't do a full A time, so I put him down earlier and he slept for 45m woke happy and we went on doing that til bedtime. Then a few times his first nap started getting longer, so I made his second A time the normal length and that nap was longer - this happened more and more frequently and then we were out of that trap and back to a 'normal' routine again.
Anyhow, I guess I have no REAL advice, but I wanted you to know I think you're doing an excellent job. Yes, tomorrow IS a new day, and he is perfect, and you are a wonderful Mummy.
If I think of anything that may help you, Ill let you know!
Good Luck,
Zoey