I think an R4 club would be a cool idea, but I reckon Clementine's right -the problem for organising interesting events would probably be a shortage of vehicles / owners.
When I had my first R4 about 15 years ago (when there were still quite a few cars about) a dedicated club would have been brilliant as it would have encouraged the preservation of the cars and raised their profile amongst potential owners, but alas in those pre-internet days I never really managed to make contact with other enthusiasts. I joined the Renault Owners' Club, but found it a bit too dull and bearded (apologies to any ROC members reading this!!) so soon gave up on it.
Maybe it might be worth trying to organise a small stand at one of the national classic car shows, although that inevitably means an investment of somebody's time and money (at which point interest may suddenly evaporate... :cry: ). It would be one way of testing the water though.
As another idea, what about gate-crashing a 'rival' event? I remember being gate-crashed at the 2CVGB national meeting about 5 years ago by a swarm of Messerschmitt bubble-cars (including a friend of mine being chased around a rugby field by one!), which was unexpected and amusing. Maybe gatecrashing a 2cv event (the 2cv being the R4's nemesis, and most 2cv owners being a light-hearted bunch) in a small convoy of R4s and challenging them at something bizarre (a motorised custard-pie fight in the respective vehicles?) might create a positive reaction? :shock:
I think the Slow Car Club's drag racing event was an amusing idea, and maybe if it became an annual event it might be possible to attract enough R4 owners to have an impromptu R4 meet simultaneously.