Kodak (and presumably other companies) invested significant research into speeding up all kinds of photographic processes, as exemplified by their C-41RA (rapid access) process line. Speaking of C-41RA: if you look at the
process manual, C-41RA colour developer uses the exact same process times as the standard C-41 process, the real speedup comes from faster bleach, fix and wash procedures.
Where does this leave us with E-6? First of all, we have two separate developer steps, which apparently can not be sped up without sacrificing image quality (see C-41RA, but also PhotoEngineer's comments). Both E-6 developers are already quite concentrated (FD is mixed 1+4, CD is mixed 1+1+3 from their respective concentrates) and very active (E-6 FD would develop Tri-X in less than one minute at room temperature!), so increasing their concentration may not give you much faster action anyway. Also, E-6 material was never modified to use the faster Ammonium Ferric PDTA bleach, and with Ammonium Ferric EDTA bleaches you can't really increase concentration all that much with positive effects on bleach speed (say hello to ionic strength!).
This leaves you with fixer and washing, the only process steps which you can really speed up. You could presumably use the fixer from C-41RA and some aggressive washing procedure (38°C water, strong agitation, frequent water changes), but the overall process speedup will be less than 50%, and you'd need strong evidence that your high speed wash procedure keeps process liquid carry over under control and gives archival stability of your final result.