Ok, I think that I have found a few reliable manufactures of roller rockers for my 360 rebuild:

Comp Cams: magnum roller rockers: 3/8in stud - require screw in stud & guide plates - dont have roller pivot or polylocks. $145 http://www.compcams.com/Technical/Catalogs/106-03/HTML/310.asp
Crane Cams: Aluminum roller rocker: 3/8in stud w/ polylocks - require studs & guideplates. $195. http://www.cranecams.com/?show=browseParts&lvl=3&prt=106&action=partSpec&partNumber=11746-16
Crane Cams: Aluminum roller rocker: 7/16in stud w/ polylocks - require studs & guideplates. $195. http://www.cranecams.com/?show=browseParts&lvl=3&prt=106&action=partSpec&partNumber=11747-16

I really am leaning toward the Crane Aluminum Rockers since they have the roller pivot. Not sure between 3/8in and 7/16" studs though. Are there other brands that are comparable in price? I don't really want to spend more than $200 for a set of rocker arms. Most other kits start above $300.

However, I am still wondering about push rods & guide plates. I know that to run guide plates you need to have hardened push rods which shouldn't be too hard to come by. (haven't found anything yet - what length do I need?)

However I have never seen anybody selling AMC guide plates. Who makes them? Are guide plates/hardended pushrods really required for switching to roller rockers? Also, when converting to roller rockers with polylocks, will these fit under the stock, short AMC valve covers? I have seen that Milodon makes tall-chromed valve covers four around $55 and Edelbrock has similar for $48.