Multitools that fold are awkward but the SKS Toolbox Race or Tour require the least extra bits to work with a Rohloff bike; I don't carry mine though.
On my Rohloff hubbed bike I carry:
Topeak Toolbar, 68g, looks like a toy but is a serious tool, fits one bit from inside at a time, carries more bits in holder on keyring at back if required (I don't), sides slide out to become tyre levers, highly recommended:
http://www.sjscycles.co.uk/topeak-topeak-toolbar-compact-multi-function-tool-prod16114/T20 bit, Witte, very high quality, fits Toolbar, kept inside it
8mm hex bit
Extension bar from another toolkit, necessary to use Toolbar to get at adjusters for Magura Hydraulic rim brakes
8x10mm open spanner, for emergency gearchange if cables break, for mudguard and BUMM light fixing nuts
Brooks saddle tension spanner, special from Brooks
1/2in socket for adjusting Brooks seatpost clamp
1/4in hex to 1/4in square drive to drive above with Topeak Toolbar
Small plastic pill tub to hold these loose pieces together
Spoke spanner
Park glueless patch kit, about the size of a postage stamp and not much thicker
Old style big coin for turning flat battery covers on HRM and bike computer
Electronic tyre pressure gauge
Kitchen tissue for stuff
Plastic bag for rubbish or heavy rain
20 Euro note for emergencies
Mobile phone, switched off, only switched on for emergencies
All this fits in a tiny bag, actually a small lady's leather coin purse which has been variously hung on tiewraps behind the saddle, tied to the seat tube, and now hangs unobtrusively from the rack toprail.
I don't need a chainbreaker as I use two quicklinks on my chains (my bike's wheelbase is so long, I need 126 links in the chain).
This will do everything on a modern bike, short of removing the crank.
I'm thinking of buying a Knog folding adjustable spanner to replace the 1/2in socket, its adaptor, and the 8x10 spanner. It will have an additional use as a pedal spanner, which I need because I replaced modern pedals with a hex socket on the inside with vintage Phillips pedals (to get more pedal under my foot) that don't have a hex socket.
Andre Jute