Is there a way to place a maximum field size (in characters) on a memo field? I don't need the whole 65, whatever thousand but I need more than a text field provides.

On the table design, the memo field has a Validation Rule.

I don't necessarily think you can limit the amoun of characters but you can definitely stop it allowing more than a specific number.

e.g.

Len([YourField]<=500

That would limit the memo field to having 500 characters - any more and the user will be informed that they have exceeded the limit.

Don't forget to change the ValidationText either, otherwise the user will be given a rather ugly message - much better to customise it here.