+1 on the SKS Chainboard. I have three bikes fitted with SKS Chainboards, two IGH and one 3X9. The Chainboard doesn't need any special modifications for front derailleur clearance as there is a square removable tab on the top forward portion of the guard that easily removes (breaks free) without any specialized tools creating a notch for your derailleur to move back and forth within.

Now, my IGH Dahon Cadenza w/eccentric bottom bracket, that did require some ugly and somewhat hamfisted modifications. :shrug: