Dynamic of growing blog

Hi,

in our company are the blogs mushrooming up, we have already 66 blog (whitin 7 months). Some of them were alraedy deleted or deactivated, but most of them are still active.

Each blog has 26 own tables (wp_<blogid>_ ...), in total 26 * 66 = 1716 tables. To our first anniversary we will have nearly 3000 tables.

Question: was WPMU designed for such dynamic:

a) creating 2 blogs in the week
b) deactivating / deleting 2-3 blogs in a months ?

Is there an useful limit for blog count ?

Thanks in advance,

Michel