Top of the line skate rollerski boots by Alpina. Width is about average, and snug heel. If you want a narrow carbon boot, the Spine Ultimate is good choice. For wide feet, the Botas RSC.  

Compatible with NNN and Prolink bindings. Come with half size volume reducers.

Stiff boot flex
Power strap
Plastic heel counter
Anatomic footbed
45 degree lacing system
3D shaped carbon stabilizer
3D shaped asymmetric, removable carbon cuff

We measured the inside lengths (stuck tape measure inside boot with insole in) and got the following lengths:

36 Euro: 9"

You can measure your foot by backing it up against a wall barefoot and measure out. Generally for summer sock thickness and to ensure toes aren't rubbing on front, you want a boot that is your foot length plus ~1/2-5/8"