Could the 'automatic' chunk size use the size of the currently generating page to know when to start another page?

Right now we 'guesstimate' what the appropriate chunk size will be, but this does a poor job if some links have a lot of additional data, like image or video data attached to their sitemap <loc> records. This results in having to lower the chunk size down even lower, and some sitemap pages with very uneven links and filesizes. It would be nice if the file generation could be 'smart' and detect how big the file is getting, and when it nears 10 MB, to stop and generate a new page.