I've been following this thread closely
I've just been making enquiries for a customer on the very same subject and have discovered the following.
JHP's fork bottoms are indeed for 108mm mountings, as are just about every other conversion available.
However, JHP are now doing some made by MotorCorse for the 100mm calipers.
These are £823+vat, but the calipers are a lot cheaper than the Brembo Race. circa £200 each.
The brackets that are available that convert the standard mounts to radial are, by general concensous, only any good to achieve the "look". Again, as mentioned above, they seem to have an adverse effect on the braking. Doing nothing for the stiffness of the assembly and in some cases creating vibration.
That is the opinion of suppliers etc. I have talked to. Couldn't comment personally
Still expensive, but have to agree with Neil.......thay don't half look good