Help me with brake discs for my R90 please

[dalla]

Hi guys

As some of you might already have noticed, iam building a R90 cafe racer.

I am using a K100 fork, with snowflake wheels. I need some brake discs for this setup.
So far I have been looking into some custom made ones, but would rather run OEM looking discs.
Ideally I need 280 mm discs with 46 mm offset. But I can adjust the offset a bit.
So my question is, are there some 280 mm OEM discs available, that will fit onto my wheel?
What offsets are available? Alternatively have any of you tried to get a bigger diameter disc mounted to the OEM brake hub? What I am thinking is wether it is possible to get say an R45 disc assembly modified to 280 mm?

Hope you can help.