Luey - I'm chasing you round the sleep threads today!

We had great success with the no-cry solution early on, until things went to poo a couple of months ago (explained in that other thread....)
Now DS is sooooo much like yours. Sometimes, if he's absolutely knackered, he'll feed to sleep (but not without a struggle usually), otherwise only my DH can get him to sleep, and only then with a lot of effort. Sometimes, he just WON'T, just like your boy. He sleeps 40 minutes at a time max during the day, and lately only 1-2 hours at a time overnight (though we did have a much better night last night, though who knows when that might be repeated.)
He's exactly the same with grabbing our hands or slapping them away. Or he's scratching at the cot rails or thumping the mattress...
I know lots of people say you should avoid eye contact or smiles or whatever when you're trying to get babies to sleep, but for DS I think the opposite is true. Particularly if he's upset, we get him laughing first. Do the things he loves, so he's relaxed, and try again. Sometimes, once he's relaxed, something monotonous - like singing the same tune over and over or shhhing - will get him to drop off.
Sorry I don't have any real advice for you. The last time DS was this overtired we broke the cycle by getting him to sleep 5-6 hours a day by carrying him round in the HUB all day (or rather, my DH did). But not sure that we could do that now...
Certainly hope that things improve soon