I think the Motorola (Freescale) MCore is 68k-like also. And as others have said, the ARM would probably suit your fancy too (Atmel have some decent parts and tools).

I would also like to reiterate that if you are working in C, many of the particulars of the CPU are hidden enough that the choice of CPU isn't governed by the CPU instruction set. As funky as the 8051 is, the C compilers (Keil and others) do a very good job. I even have the horror of using some mental Cypress 8-bitters, and the C-compiler there (ByteCraft) has made single-register assembler gymnastics a non-issue.

GB