Essentially, using a network install (as mentioned here) would be just as slow as downloading the ISOs from a mirror? Not a pleasant option, even with broadband.
Not really. You wouldn't download ALL of the packages if you were doing a network install. You'd only install the ones you selected. it is rare that someone installs EVERY SINGLE PACKAGE.
The last time I did a network install was with RH5.2 way back when, on my then cable modem. Not fun - a basic install took all night to run, and I've never touched network installs since (off the Internet. I do network installs off a LAN frequently).
You need to look up better mirrors.
I hardly know anything of the internal workings of Anaconda, but perhaps there is a way to do network installs of bittorrent shares? Now THAT would be interesting!
Extremely hard, in fact. Bittorrent normally hosts only the isos, not each package.
-sv