Just got off the phone with Lutron, and it appears that the RadioRA 2 upgrade program is still available. The only catch is that I have to go through a dealer to get it. I'll be calling around for estimates, so we'll see how that goes.
If the price is too high, I'm trying to figure out how to do a rolling upgrade throughout my house to even out the costs, and gradually phase out my existing halogen bulbs. I can certainly do this by starting with rooms that have Lutron dimmers that are not wireless. That will get me three zones at a minimum.
For the next phase, I'd like to start upgrading individual zones over time. The only catch is that I'd need to run one RadioRA classic repeater and one RadioRA 2 repeater, switching dimmers from classic to 2 as I go.
Is that a working strategy? In particular, can I have a RadioRA classic repeater and a RadioRA 2 repeater working side-by-side?
Finally, if I'm going to be doing a whole-system change, are there any other wireless dimmer systems I should consider before continuing with Lutron?