Does gdb really support 16-bit pointers now? Otherwise I don't see how you can step through 16-bit code. And even if 16-bit binaries are not really important, support for 16-bit pointers definitely is.
I responded to fast. Of course, only the stepping thru wine's builtin 16 bit modules is available (but that's 32 bit code) For pointer deref, one quick solution is to add one command to gdb which converts a segmented pointer into a linear address. Then this linear address can be used in any gdb command (it'll much more harder to add segmented pointers support though out every expression)
A+