Well... If you go to download.com you can get a copy of Bryce 5.5 free.
http://www.download.com/Bryce/3000-6677_4-10696716.html?tag=lst-1
This is a 122Mb download so you have to have a fast connection.

For me it was only about 10-20% faster than 5.0. It does handle multitasking in windows so you can use your other programs while it is running. Not a great improvement...but it's something.