Am I just missing the point again, or wouldn't this concept of a "Wikipedia Ombudsman" duplicate much of what a member of the Mediation Committee would do?
Maybe an Ombudsman would have a special power or two that the average Admin wouldn't have or need (say, the ability to force both parties to negotiate in good faith or suffer sanctions), but I wouldn't be surprised that whatever shape the position might have, it'd have a rate of turnover somewhere between the ArbCom & the Mediation Committee -- that is, we'd burn thru one Ombudsman every 4-7 months.
Just my $0.02,
Geoff