Those SUV adapters make me nervous, based on my experience trying to stack the rubber blocks. The problem I've seen is that the QJ doesn't lift straight up. There is some lateral movement of the vehicle as it lifts. This means that until the tires are completely off the ground, there is some drag that tends to cause the stacked blocks to lean. This is especially true if the ground surface the QJ is set on is not perfectly level. I have to think the problem would be even worse with the SUV adapter kit.
That's why I decided to use a couple of 2x12's screwed together and placed under the full length of the QJ when used under our SUVs (if needed). This gives me about 3 extra inches, which is not much less than the added height provided by the basic SUV adapters (4.4 inches).
This seems much safer to me. The tall post of the SUV adapters worries me, especially when I'm rolling around on a creeper under the vehicle. They just don't seem that stable looking.
The 2x12s are also a lot cheaper than the $220 SUV kit, although not as convenient.
As far as accessories, some caps for the hydraulic fittings would be nice. I use a couple different sizes of crutch tips you can by at Ace or Home Depot. The 1 1/8-inch size for the female fittings, and 7/8-inch for the male fittings:
Mark