I have one that is just under 4 mb with 4 data connections. However mine has a bunch of user views and also contains a bunch of images. It runs fine as a web enabled form for 90% of my users. Some users in remote areas with slow connections experience a delay in loading the form and some of the views take up to 30 seconds to load.
I think this is a large file but im sure that are some out there that are much larger for those who use many data connections, especially those related to products and inventory lists etc..
Hope that this is helpful.