I did a little research, and I am using a set of Gabriels from a Ford (rears from a 4x4 F150) as front shocks in my '94 YJ. I'm running 3.5" springs with 1/2" boom shackles, and so far so good. I haven't checked full flex, but ride is comparable with my stock springs and shocks.
I did a lot of internet searches, and was able to find a Gabriel shock that had comparable specs to the (length, travel, etc) shocks found in most 4" lifts. Now, I did intentionally go with a cheap shock just in case I ran into any problems, that way I wouldn't be out much. In fact, I think I'm into the pair for less than $30 shipped.