In the beginning starting area there should be an option to have an "iron-man" option.
This option would automatically set you to the challenge mode that is iron-man.
Block outs for:
heirlooms and dungeon finder, riding training until 40 and epic for 60, re-spec should cost gold.
You could also create iron-man servers? Like when flagged for pvp a group of players shard into their own server per say. That way iron man players can group together and take the challenge on as a group. May be an easy fun feat for players looking into that.