We're going to leave it a tandem.
The debate rages over which is better.
Our feeling was that the nominal decrease in turning radius, saved weight, small mileage gain, and storage space were more than offset by having more tire on the road - just in case.
It'll never be a 4x4 but I'll take 6x4 over 4x2.
Plus it cost about $1500 to drop the axle and shorten it - even more if you want to leave it long.
We mounted a pair of old fiberglass dock boxes on the back along with the Stand Up Board, mountain bike, her commuting bike, and the tandem.
I'm going to keep my tools and other heavy stuff in the back over the rear axles. When we've got the trailer hooked up it should give us about 25-30 lbs in the airbags. Should soften out the ride a bunch.
I'll post some more pics when I get a minute.
Cheers,
Mark