I just installed RedHat 7.0 and set about configuring it and was stymied by what appeared to be a problem with xterm. Whenever I pressed backspace, the code submitted to xterm was (from memory) ^[[3~, which of course doesn't do anything useful. So I began working through the xterm manpage to find if there's a resource that could be the problem. No luck. Then I switched the XkbLayout back to "us", and lo and behold, it worked. Further investigation revealed that the key symbols associated with <BKSP> in /usr/X11R6/lib/X11/xkb/symbols/dvorak did not match those used by /usr/X11R6/lib/X11/xkb/symbols/us--the dvorak key symbols were "BackSpace, Delete", whereas the us key symbols were just "BackSpace". Changing the symbols in the dvorak map fixed the xterm problem.
I use a dvorak (soft mapped Happy Hacking) on the 7.0 and 7.1. I can't seem to reproduce your problem.