RANS has developed the RAC cargo system which is a subframe that bolts on to a RANS crank forward bike and comes with two large bags. Looks like a nice option in between panniers/rear rack and an Xtracycle.
"RAC (ride and carry)
The bike inspires the commuter, and the short haul shopper, and is a natural for our new RAC cargo system. The bags and rack for the RAC system are custom designed for our CF line, and produced in our Hays plant. The system comes in two sizes, a large and standard.
The large measures 27 X 9 X 15” and the small 24 X9 X15” with cubic volumes of 2.1 and 1.9 cubic feet respectively. All of our current and many past CF offerings should accept the RAC system. The bags feature Lexan shaper panels, with several lighting holes for reduced weight. A maxi and mini bag and rack set adds 11 and 10.75 pounds respectively. Bags weight 4 pounds or less, and racks are 3 to 3.1 pounds typically. It is a worthy weight hit in the form of a very stylish bag set and rugged rack. The tubular frame is designed using alloy aircraft tubing, and our special fittings. This construction has been flight proven on our planes, and is ready for daily street duty.
In case you over buy, the bags contain an extra flap, that will extend to cover the items. I have also found it handy for transporting a bike. To haul a bike: place the front wheel in the bag and tighten the flap over the wheel and your ready to roll. I was surprised how often I used this feature, so I installed a bike hitch. The hitch is made to clamp the front fork., and no, it does not work to try and ride the bike that is attached to the hitch, at least we have not found anyone with the quick reflexes it would take to stay upright! We half jokingly showed the bike hitch at Interbike, but many thought it to be a very useful option, so it may make it into the offerings in due time.
Other features of the bags include: Side mesh pocket, reflector strips, handles on each end, and wide color selection. Constructed of 9.1 ounce Cordura, the bags are carefully crafted at our Hays Plant to endure many miles of use and abuse.
Read more about the RAC here.
High rack and frame torsion strength allows carefree loading. The bags seem to hold up to this sort of use, but I prefer to balance the load, rather than feel a slight turn tendency. How much can be loaded? About 50 pounds per side seems reasonable. That is a lot of groceries. The RAC system is not really intended for human cargo, but of course, we have tested it, and set the max loading to 175 pounds, so it splits out like this, either 50 pounds in each bag and 75 on top, or a single 175 pounder freeloader. We may have an optional top deck, and runners, similar to the HammerTruck rack. Expect this system to expand with such options to increase utility in the near future."