I've never seen another v-brake set that does what Motolites do. What does exist for much less, though you'd need to change levers, is the old Tektro tri-align cantilever brake:
I'm not 100% sure they have the 12.5mm-ish of height adjustment to spare that you'd need, but probably. You could figure it out from scaling the pictures and measuring the axle to boss dimensions on your bike.
Apparently there are also similar Avid and WTB brakes.
If memory serves they are not the nicest brakes in the world to deal with, but I don't have experience with them beyond randomly encountering them a handful of times. They're a low-profile canti design, which has a lot of disadvantages on a touring bike (geometry slips out of optimal range quicker and needs adjustment more often). Being a canti these do offer the benefit that you'd get to dial the mechanical advantage by running a lower straddle to compensate for the pads being higher than intended away from the post.