A four point roll bar would be sufficient unless you're running faster than 12's, I think it is.
Jeg's has premade 4-point rollbar kits that you have to weld together, that's about the only thing I know of. They have bigger kits too (6 point, 8 point probably) but like I said, you don't really need those.
Eventually or one day in the far future.... I hope to get a 302 or 351 to stuff in the mighty mighty LX. I don't want to drag race, but maybe take it to track days and check out some of the road race stuff.......
In that case, why not wait until you get that engine in and THEN buy the rollbar? In the meantime you could get some subframe connectors, Fox verts really need them because they don't really have any additional bracing to help with the absence of a roof.
Also, I don't think a 4 point bar would do very much stiffening since they mount to the rear wheelwells, and then behind the seats. You'd need at least a 6 point to see any benefit there.