As Del says, merchandise was fruitful in the past, requiring volunteers to give their time to manage orders, payments, production and distribution. The biggest advantage is that they were done and sorted well beforehand, rather than in the midst of the hurly burly of Le Mans week itself. But that was in pre-Faceache days, when more CAers were on the forum routinely to respond to stuff, rather than just being on it in the immediate few weeks before the race, as is the case for many now. So we would need to get the word out other than just through posts on the forum, but that shouldn't be difficult via email or if we are contemplating a Faceache page or similar.
The prospect of watching money roll in as an adjunct to Rex poledancing is an entertaining thought, but one, I venture to suggest, that would be very difficult to manage effectively in the fluidity of the Friday evening carnage that is chez our dear Brethren. Maybe there is an alternative - the "CA Gathering", is advertised in the Guide for a Saturday evening - I don't know about others, as I've only made that once as me and mine tend to be out around the circuit at that time, but it's a busy time and full of the public around and about the area - could it be arranged instead for, say, the Thursday evening in the hour between the qualifying sessions, or sometime on the Friday, before and separate from the Brethren party?
Old school tin rattling by extroverts wearing some fancy garb around the campsites is another means. Perhaps get that supplemented by some mentions on RLM so that people are expecting it (John Hindhaugh is a sometime contributor to the forum, so could be contacted to ask about getting the odd mention on RLM).
The charity auction, IIRC, was mainly for items/experiences that had been gifted through various CA individual's contacts with race teams (e.g. signed gloves, posters/artwork, visit to a team's pit during the race etc). However, with the advent of instant social media and the ebb and flow of various groups and people attending Le Mans, I suspect that recreating the days of the DFH party, sound stage, Flying Baguettes concert with the charity auction would misfire. However, the charity auction concept might be a possibility if it were done online provided enough people knew about it, or on air (revert to earlier comment re RLM)?
MG Mark