I think the 68K came fairly close to what you guys are asking for, with its addressing modes like (a0)+ and so on. it's only 32 bit but that's better than 16 bit :) the problem I have with 68K is that while the assembly language is basically orthogonal the machine code is not, there are too many exceptions in the encoding, which I think was done to save precious code space. (Kind of like ARM Thumb code -- and by the way you may find ARM more PDP11-like than the other archs you mentioned). Anyway, some of the latest 68K such as Dragonball(?) have gone some way towards correcting this deficiency by not implementing many of the more irregular insns.
cheers, Nick