Ok...
The MySQL space limit is an idiotic limit, the MySQL database size should reflect that of available disk space for the user. Modern control panels such as Ensim or CPanel or even Plesk will take this into account.
The limitation would thus be anything available to the users total available webspace versus a MySQL space limit. So if the user has 8 gigs of space, their mysql limit would be anything they would want up to their 8 gigs of space.
Honestly, if your webhost is enforcing these limits, you should look elsewhere as there are plenty which don't have such insane limits. Then theres always VPS' which are as low as $30 at some places now adays which is at times more than some people are paying for virtualhosting...
