Azcap21. If I understand your goal correctly, you're starting from stratch, and you'd like to control 64 channels and make them dimmable, not just on/off.
One 595 controller board will control 64 channels but is not dimmable by itself. There is currently a design under testing (beta) called the REN-C that can add dimming to a 595.
There was a large coop for 595 boards earlier this year. I doubt another one will take place. So I don't think that's going to be an option for you this year.
There is an alternatve to the 595 called the GRINCH. WJOHN on this forum has some boards. You can PM him or post in the GRINCH forum. The GRINCH also does not do dimming by iself. It will be compatible with the REN-C, so once that is out of beta and someone runs a coop order on more REN-C boards, that might be an option for you. This might be your best option as the GRINCH is relatively simple, so you could get started, and think about adding dimming later.
The best option if you want 64 channel and all dimmable from the start is the Renard64 board. You'd be in luck, because there is currently a coop running right now. You'd have to decide fast. Once you're read to commit you can post your intention in this forum.
http://www.doityourselfchristmas.com/forum/viewtopic.php?t=443 Be read to paypal WJOHN some money when he gives us the final price.
You can start reading about the Renard64 controller in this thread. It has links to a historical forum and also a link to the current WIKI.
http://www.doityourselfchristmas.com/forum/viewtopic.php?t=399
Keep in mind, none of the controller boards I list above (595, GRINCH, Renard64) come with the parts. They are just bare printed circuit boards. The bill of material for each board is generally in their respective forum somewhere or on the WIKI.
Keep in mind too that the Renard64 will require you build a transformer board or otherwise select an alternative for supplying a 'zero-crossing' signal (necessary for dimming).
http://www.doityourselfchristmas.com/forum/viewtopic.php?t=281
The Renard64 will also require PIC programming. There might be a coop on the PIC's and the person running this might volunteer to do the programming. Check the COOP forum for this topic.
Lastly, keep in mind these are all just controllers. By themselves they do nothing. You'll have to have SSR's. You best option is to ask WJOHN if he had 16 SSR bare printed circuit boards for those and order the part / build those. (There are 4 SSR's per board thus giving you your 64 channels).
Ballpark figures (I'm just guessing), Renard64 will end up costing $80 to build. 16 SSR will cost ~ $180 to build. Extention cords, lights, cat-5 cable, I dunno, maybe another $100 - $200.
Time necessary for all this is hard to judge. Let's just say it will be a substantial number of hours, but mostly fun I think.
Hope I understood you right and did not waste 10 minues composing the post.
Best of Luck.