Larger Text Field & Web

I have dilemma… the RT Lite field (using HTML) provides a larger text area than the standard text field on the web. It works fine if no additional computations are needed. I understand the RT fields can only compute once. I need the ability for someone to select a drop-down and it re-populate the fields (like text fields can). Can I make a standard text field larger (height/width) using HTML attributes, etc.?.. about equal to a RT Lite using HTML is fine. Thanks in advance…