[Sca-cooks] vegetable stock

[Lonnie D. Harvel]

Greetings!

For my upcoming saxon feast, I need a goodly quantity of vegetable 
stock. I prefer to make it rather than buy it. I often make my own, but 
in much smaller quantities, and for contemporary purposes. Does anyone 
have any "rules of thumb" regarding rations? A recipe perhaps (seems 
silly for stock, but I guess that is what I am asking for).

I will need 60 cups for one dish, and would like to have at least 
another 20 cups on hand for other uses. I plan to make all of my 
vegetable dishes vegetarian (ovo-lacto) so I will need some flavorful 
liquid that does not contain meat.

What I have in mind so far:

Good ol' mirepoix (onions, carrots, celery)
salt
pepper
bay
marjoram
(I often picth a rudabega in if I want a more earthy flavor. Are those 
period to 10th century England?)
butter
water

Suggestions welcome. Here is a pointer to the feast if you want a context:
http://www.brynmadoc.org/danelaw14.html#feast

Thanks,
Aoghann