That said, it's just a pet idea... especially since there is (was) Freeradius.net, and I'm always open to seeing good *nix tools/servers porting to Windows.
In case someone is remotely interested in FR for Windows, this is what I see when I type in: radiusd -v radiusd.exe: FreeRADIUS Version 2.2.0, for host i686-pc-mingw32, built on Mar 17 2013 at 02:22:49 Build options: OpenSSL 1.0.1c | OpenLDAP 2.4.32 | Heimdal 1.5.2 | MySQL 5.5.28 | unixODBC 2.3.1 | IKEv2 0.2.1 | Hiredis 0.10.1 | IPv6 Copyright (C) 1999-2011 The FreeRADIUS server project and contributors. There is NO warranty; not even for MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. You may redistribute copies of FreeRADIUS under the terms of the GNU General Public License. For more information about these matters, see the file named COPYRIGHT.