As a temp fix until technology catches up to demands, maybe offer sending more files but have a "Download 1-50" and a "Download 51-100" etc. or "Download page one", "Download Page 2" and so on... The idea of sending more but without a download all button doesn't appeal much to me. Most of my clients want all the photos and would like to see them online and download selects if needed. (hence why I don't just .zip the files myself. I would be happy with having the client having to do more than one download all button if more than 50 files.
Would 100 files be out of the question? at least for me that would cover 90% of my business.