Command-Line tool to find large files on a Linux system
Some observations:


Use a main function and the argparse module pull out an argument parsing method to make this scriptable.
"larg" should be "large"; getsize should be get_size, fpath should be file_path. Saving characters costs a lot of money in maintainability.
As @Edward wrote, don't keep the entire list of files in memory. As a counter-point I would have liked for the results limit to not exist - the default behaviour would then be simpler to implement, and would return every file in order of size.
In addition to excluding directories you should make sure that you don't follow symbolic links, or you could end up with an infinite loop.
The OSError in this case should be fatal - it indicates that your program is faulty since it doesn't properly filter files which you can't get the size of. I believe it could also happen if a file is not accessible, which means any result you get from this script might be inaccurate.
Replace **kwargs with excludes=None, followed by a simple excludes = [] if excludes is None else excludes. That way the parameter list is unambiguous. Even easier, make excludes mandatory (you are always using it anyway). YAGNI &amp; KISS apply :)
It looks like your handling of exclusions doesn't anchor the regex at the start of the filename, so you'll end up excluding for example /home/user/dev.
excludes in walk is always truthy. You should either remove the or r'$.' bit (best option IMO) or get rid of if excludes:.
You reuse excludes in walk to create a completely different list. This is a bad practice because it makes the use and content of a variable really hard to follow. Use separate variables for these.