I'm just starting out in Objective C and I really miss textmate.
I saw there is an Objective C bundle, but as you said the problem are those really long method names in the cocoa/cocoa touch frameworks...
In the AS3 bundle pressing ctrl+h the Adobe documentation for the current tag pops up, and you have also a command (cmd+enter) for telling flash to compile the swf file. I suppose it should be possible to do the same for objective C.