I'm sure alot of people around here have a copy of that Griffin show, if you can find someone willing to trade. There's a good discussion of it right now at the "a_film_by" newsgroup.
Welles on Merv Griffin thread
Here's a quote from that discussion mentioning another Welles TV appearance that would also be great to get a copy of:
"One memorable 90 minute tv appearance was when Welles acted as guest
host on "The David Frost Show" circa 1968 or '69. He said he'd been
out of the country for awhile and so was going to hold a "teach-in"
to catch up. Among his personally invited guests(who were seated in
the audience)were a feminist, a black power advocate, a member of the
Socialist Worker's Party (probably the only time in tv history a
Trokskist got a respectful hearing)and a memeber of Young Americans
for Freedom (a conservative youth group.) The rest of the audience
got to respond too. What Welles did was to brilliantly craft the show
into a truly democratic town hall debate on the issues of the day
with himself as moderator. Maybe this show should be included in his
filmography?"