Unfortunately the max limit is set to 100MB and cannot be updated at this stage.
As a workaround If needing additional storage you can use an external storage like (dropbox, etc). Then for the e-product file upload the instructions (doc, pdf, txt) for the customer on how to access the product once they purchase.
Hope this helps!
BC can either hook into the cloud or just allowe Amazon S3 integration.
You have a 100mb limit but then you can choose to store literature items/other media via Amazong. If you enter your details it shows a connection to upload/download on the S3 for a folder that specific for those means and only stored there. Something along those lines.
I found a solution a while ago which might help you all out. What I did is created a blank HTML document with the following code in it then update the link to the address of your file. Once you have done that upload the HTML doc - what it does is automatically redirects the person to the file and starts downloading it. It is probably not 100% secure for your content but is the best method I have found to date.
Let me know what you think.
<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Transitional//EN" "http://www.w3.org/TR/xhtml1/DTD/xhtml1-transitional.dtd">
<meta http-equiv="Content-Type" content="text/html; charset=UTF-8" />
window.location = "http://www.yourdownloadlink.com/download.zip"
I put together a test of the solution you posted. It would work in terms of getting the product to the customer. I really don't like the extra step for the customer, the lack of security, and loss of control over who can access the file(s), though. Still it is the nicest work-around I have tried for this problem.
So here is another plea to BC to get this fixed. 150mb would allow me to offer most mp3 albums in 320kbps quality. 200mb and I wouldn't have to worry about a 75+min album getting in under 150mb. Or, just allow multiple files to be downloaded as one product in the catalog. For now I have to make mp3 albums 192kbps quality, and it is just scraping the bottom of the barrel of acceptability.