Have you tried the 'rowheight property?
Try this:
0010 LET x=10
0020 LIST_BOX x,@(5,5,17,10),OPT="r",FMT="[Name]8 [Type]8",SEP=","
0030 LIST_BOX LOAD x,0,"Puss and Boots,Cat"
0040 LIST_BOX LOAD x,0,"Marmaduke,Dog"
0050 LIST_BOX LOAD x,0,"Piggly Wiggly,Pig"
0060 LIST_BOX LOAD x,0,"Dumbo,Elephant"
0070 LIST_BOX LOAD x,0,"Scrooge McDuck,Duck"
0080 LIST_BOX LOAD x,0,"Mickey,Mouse"
0090 LET x'Rowheight=1.5
0100 ESCAPE