If you know you're going to be doing a 4x4 conversion in the next year, I wouldn't do a lift. I lifted my van with a camburg kit (although I didn't think I was going to do a 4x4 conversion), then did the 4x4 conversion shortly after. I sold the lift for over $1000 less than what I paid and it only had a couple thousand miles on it.
On the other hand, if you're planning on doing a UJOR conversion, then just buy the hangar kit and front axle, and install that now. Then do the rest of the conversion when you have the time/funds to complete. That would be the only way to do a lift, then use the same components for the full 4x4 conversion.
2005 E350 Chateau - V10 - Agile Offroad 4x4
2012 CTS-V Wagon - For the baby...