Is it possible to provide the following type of fuctionality with informix client tools?

As the user types the first two characters of a name, the drop-down list is empty. At the third character, the list fills with just the names beginning with those three characters. At the fourth character, MS-Access completes the first matching name (assuming the combo's AutoExpand is on). Once enough characters are typed to identify the customer, the user tabs to the next field.

The time taken to load the combo between keystrokes is minimal. This occurs once only for each entry, unless the user backspaces through the first three characters again.

If your list still contains too many records, you can reduce them by another order of magnitude by changing the value of constant conSuburbMin from 3 to 4.