Most common lifts will yield 3 -3.5" of lift. You have lots of choices from OME, Donahoe Racing, SwayAway, King, Fox, etc. Lots of good kits out there. I woudl say stay away from spacer lifts. Thus you will remove your XREAS to fit any of these.
If you want to go 4' or higher, you have a choice of getting a Total CHoas Long travel kit (which is a high performance lift kit). Or the cheaper more simpler drop bracket kits (which are loved and hated) from Procomp or Fabtech.
You can also add a bodylift to create more space for larger tires if you need.
See this for more info
http://www.toyota120.com/forum/showthread.php?t=424
Needs to be updated wth more info on the new kits, etc though. Or just go through here
http://www.toyota120.com/forum/forumdisplay.php?f=11