DS stopped napping at 15 months old. and DD stopped napping at a year... she napped on occasion, but nothing was ever set in stone. neither got irratable either... even if they both were napper, by 2 years old, i wouldnt have allowed naps.. both my kids are early risers too, 6-7am and in bed by 9.
My DD at 2 years was phasing out naps. Every once in a while when she is overly active in the mornings will she go down for an afternoon nap. It would take me up to 6 books until she would pass out on her worse active days. She would wake up at 6am and go to bed around 10pm.
If you can afford to burn some gas, I would say take them out for a 30 minute drive.
Try setting up a new nap routine around mid-afternoon after lunch, a physically active activity and then some quiet time activity like coloring, putting together a puzzle or play-doh.
Try enforcing a quiet time for him to be in his room, I would have my son lay on his bed and tell him I would check on him in 20 min. If he was tired he would fall asleep, if not I would let him play quietly in his room or watch a movie while the other kids slept. He needed a nap about every 2-3 days. and he would get up around 7am and be up till 10pm. I needed quiet time!!
I don't find it to be odd. Every kids is different. Ds1 stopped napping at 15 or 18months. Even before then he wasnt big on sleep. Ds2(6) still naps when I let or make him. He never seems to have enough sleep.
When ds1 was younger I would put him in his pack in go with Baby Einstein on. He always calmed right down and watched it. Once in a while he even fell asleep.
My daughter stopped napping early. It was no fun for me! She'd finally fall asleep in shear exhaustion every 2-3 days around 4:30. My husband would come home and want to wake her up and I would tell him, not unless he had a death wish! She would get so cranky and whiney and any tiny little frustration would make her have a melt down.