what should we work on for the near future?

Hypothesis; How much Liquid methane from a CBC can be cross feed into a liquid Hydrogen  Core stage with out modifying the core engine?

Much work and talk on Methane powered launchers(SpaceX,

Much work and talk on LH2/LO2 systems and Fuel depots(ULA)

Some talk on Hypergolic fuel depots

all of these make sense but involve R & D costs and may have some incompatibility issues with one another. I propose we look more carefully at this paper,

http://www.grc.nasa.gov/WWW/Fuels-And-Space-Propellants/GELLED.htm

I call the concept  mixed Liquid Hydrogen slush Methane systems…………………………………

Mixed LH2 gelled with CH4 for fuel depot

Mixed LH2 gelled with CH4 for SLS CBC

Mixed LH2 gelled with CH4 for Falcon heavy

Mixed LH2 gelled with CH4 for a Blue Origin heavy

Mixed LH2 gelled with CH4 for a Delta V heavy

Mixed LH2 gelled with CH4 for CBC only with a LH2 cental core stage for all of the above.

Update 22 March 2014,

At what ratio could you mix/crossfeed LH2 gelled in a CBC with a LH2 only core without modifying  the central cores LH2 engines?This could open up several trade scenarios, The core performs best at high altitude, the denser gelled fuel performs best at launch.Cross Feeding would be done at mix  ratios as to not have to modify the core engines as discussed above.The other trade is to gell Alkanes with LH2 but a denser mix without cross feed.Natural gas augmented with additional Ethane and Propane gelled into LH2 might make a good CBC.