Have you considered what might set the spurts off (im not beng patronising its just sometimes hard to be objetive when you are shattered) eg. has he gotten out of his routine from teething, is he going through a development leap atm (my friend found her LOs sleeping got worse when she started crawling/standing/walking etc cps she wanted to be up trying it), has something simple changed like different smelling soap powder, bedding, something moved in his room. Its the oddest little things that will set them off, I remember C havng a bad spate once and in the end I worked out she was waking up seeing y Hong Kong Phooey on the chair near the bed and freaking out, once i moved him she slept again.
I cant be much help except stick to a rigid routine however you do it, we always did dinner, bathtime bottle ITNG story then bed with her army of fave toys and her cd on and if you go in as hard as it sounds use non verbal comforting. All C ever got from me was gentle 'sleepies time Caelyn' and some gentle shushing and back patting or rubbing I never spoke to her and could settle her in minutes whereas OH chats to her and wakes her right up we have fought about it so many times.
When she did have a bad period when I put her in her bed for the 1st time I wasnt prepared to do CC so I did a compacted form where I went back every 5 mins, comforted her/put her back to bed without a word then left for another 5 mins and over time i got less and less needed til she just went to bed willingly.
Hope any of that might help but it doesnt mean you are doing something wrong honey xxx