Chris,
I can't comment on the the technical side because, whilst capable of using the end product (mostly), actually understanding how it all works is an area that is alien to me. So, other than being grateful to those who do understand it all put it all together and maintain it, my comments are aimed at the more general issues:
1) Thanks for the reassurance that this august assembly of disparate individuals will remain essentially free of business pressures.
2) Blog style news sounds great - not totally up to speed with this - is posting on it restricted to registered users? If not, presumably the only down side then is that news/comment could easily just become a bunch of drivel.
3) New forums? There's probably good grounds in some ways for separating out some subject areas, and it might avoid some of the thread creep/off topic stuff, but for a lot of people ( I think) one of the main joys of this site is just that - it happens and most people like it because it's just like having a chat about anything and everything in your favourite pub, and perhaps we don't want to change the character of that too much.
4) Registration and participation should be free. If people have to pay (even a nominal fee) to get on it in the first place, then many won't bother, particualrly when others remain free. Morevoer, there is then an implied contract where a service is expected. And you have to account for it, in case anyone asks you how much you're making and where the money goes. Appreciate that you're after our thoughts. but from my perspective I would welcome a bit (not a lot!) more detail on how much cash/what kit you need to make it all work better, in non-tech speak
5) Whilst neither advertising nor revenue generating, it might generate more traffic if some of the related websites, such as Aysedasi, Maison Blanche and Pistonheads could be persuaded to feature a CA logo/link more prominently than is the case at the moment on them, which in turn might generate the sort of traffic levels that then make some advertising viable. Equally, the CA home page contains no links to anywhere related other than to Radio Le Mans and the ACO. Once you go into the forums from the home page, you can't get back to the site home page. Much more use could be made of the home page in my humble and non-expert opinion (can it be made so that you have to go through the home page to get to the forums?). headlines for latest news, merchandise, links, etc
6) Charity fund raising is v. worthy and an advertised mark up on any merchandise and a button-push donation facility is a good way to do it, plus the wider activities that some undertake and manage. If is to be placed on a more formal footing, then it needs to be completely transparent about what is happening, who is running it, who decides where the money goes, how much is/has been raised etc. And then published, perhaps via/on the home page so that the subject doesn't get submerged by the many other threads on the General Discussion forum. That way everyone knows what people are giving their time, effort and money for and what is happening to it, and the people involved in doing it don't lay themselves open to criticism/risk.
7) Merchandising carries the risk of having a bundle of non-moving stock sitting there tying up funds. For my money, some straightforward stuff like stickers, coffee mugs, key rings pens etc would probably be the most manageable place to start before moving on to t-shirts.
That's about it I think - better get on with some work. Hope there's a few nuggets/points to ponder in there for you
MG Mark