Is it possible to use a two or three chainring with an internal hub?
From what I've read about the Alfine 11 and 8, the lowest ratio is about the same, but the Alfine 11 has a greater highest ratio.  So you could use an Alfine 11 and a smaller front chainring.  Then your top gear would remain about the same, and your lowest gear would get lower.
Try this site for comparing gear ratios, I have found it to be extremely useful:
http://www.ritzelrechner.de

This link will take you to a comparison of Alfine 8 + 39T and Alfine 11 + 33T:
http://ritzelrechner.de/?GR=SA11&amp;KB=33&amp;RZ=20&amp;UF=2125&amp;TF=90&amp;SL=2.5&amp;UN=KMH&amp;GR2=SNI8&amp;KB2=39&amp;RZ2=18&amp;UF2=2125