If you downloaded Total Commander 2.51 then you can also search for files of a minimum size that you specify. Just tried out myself, searched for all files greater than 1000 M and it returned only 1 file, my Garmin Maps file which is just over a gig. This works, you just don't get a visual picture of size. BUT you can organize the results of this search in descending order of size which is very helpful.
EDIT:
Link to V2.51 cab
1. Open Total Commander
2. Navigate to the Storage Card root directory
3. Tap on File>Find Files
4. Leave everything blank except make sure to click the check box for "Size."
5. Select the greater than symbol
6. Then enter your minimum file size that you want returned.