I would think that a Saturday (this year it's the 28th) is probably still the day with the best chances that
most can make it (the problem imho is not the day we
start the event, the problem is to find a next day where most don't have to get up early..

)
And in most (? or many..) countries there's a good chunk of holidays/off-days around the time... so I myself am quite flexible (heck, it could be held on 24th for all I care - because LNOTR is even better than x-mas..!

)
-------
In the past I was quite a fan of a mid-year event similar to the LNOTR at Machwerk (drives similar if not better to Nurburgring but shorter laptimes) with 7 races.
We actually held an event there but I think the track turned out to be unpopular(?) ... well, the idea was to use a track with a "special" note...
[iirc I created a dark-version of Machwerk (FastTommy conversion) but I'm not sure it's still around...]
other tracks that come to mind which are "special" or provide for "crazy" races are
Keimola
Moon
Efexx (rel. short)
[if you really want to abandon "reason" you opt for the madly fun/funnily mad (yet drivable) 'Rollercoaster' but then it get's really "something else" compared to the LNOTR....

]
I agree. Another event with 7 times x-laps would be the format to go.