Hi M.,
I feel for you! It is so hard when your little one won't sleep! My daughter was just like your son, only wanted to sleep on me, especially for naps.
We tried the cry-it-out method a year ago when she was one year old and I was at my wit's end. It "worked" for nighttime sleep after a few nights, but was SO traumatic for me (and when she got sick a week later, all that "training" went out the window). Since it "worked" for bedtime, we tried for THREE WEEKS to get her to nap in her crib using the cry-it-out method as well. Everyone said we just had to stick to it, be consistent, be patient, not let her see us cave-in, not even once or she'd be "rewarded" for crying... etc...
Well, after 3 weeks of hearing my baby girl cry I'd had enough of it. I went back to lying down with her for her nap each afternoon (we skipped the morning nap because she started daycare 1/2 day and would either nap there or just wait until she was home with me in the afternoon). It sounds crazy, but I just adjusted my schedule to meet her needs. I STILL am used to taking a two hour nap with her in the afternoon and I make up for it by staying up 2 hours (or more) later at night when everyone is sleeping. If she has problems sleeping at night, my husband is "on duty" so I can have that time to do whatever (I'm actually working from home, so really need those hours with no interruption).
Anyway, I know it seems crazy to have to go to such lengths to get our little ones to sleep, but I truly regret making my sweet girl cry like that for so long. I worry that it really traumatized her and I'm ashamed that I treated her like that. I really hate that I did it and listened to our pediatrician, friends, and those sleep-training books. It might work for you, and that would be GREAT. But if it isn't working, try to adjust your life differently. They are small for such a short time.
That's my two cents. I hope you find a solution!!!
Sweet dreams,
H.
p.s. At night she sleeps in her own bed (in a small twin mattress on the floor), but I lie down with her until she falls asleep. Then she wakes up 3-6 hours later and comes in our bed. It used to be just 1-3 hours in her own bed, now she's sleeping in her bed longer and longer. Yippy!
Also, have you tried letting him fall asleep on you while you're laying down, then rolling him off of you, next to you in your bed? Worked for us, and then I can even sneak away, with pillows propped up around her. She did fall off the bed once, though...