Does anyone know how to expand/increase the field parameters/character input in a drop-down box?

Is this what you are looking for? The size should adjust accordingly.
Add items to a drop-down list form field
Open the template that contains the form you want to change.

Remove protection from the form template by clicking protect Form on the Forms toolbar.

Double-click the drop-down form field you want to change.

In the Drop-down item box, type the item.

Click Add.

Click OK.

Protect the form by clicking Protect Form on the Forms toolbar.
Note: The first item in the Items in drop-down list box is the one that appears by default in the drop-down list. To move the most frequently selected item to the first position, use the Move arrow buttons.

Thanks, but unfortunately no. I am familiar with all the things you listed. What I'm referring to is the number of characters per line (which is approximately 50) in the drop-down box. It appears to be a preset number determined by Mr Gates & his programmers.

Trusty old Google will help. According to this post in the usenet group microsoft.public.word.vba.userforms:

• http://groups.google.com/groups?hl=en&lr=&ie=UTF-8&frame=right&th=d3fcdc93841fe605&seekm=0a6201c36b19%242747fed0%24a601280a%40phx.gbl#link3
  

the limit is 50, but you can get around it using VBA.