This is a very exciting new product coming soon from OS Giken.
The stroker kit for L-series 6-cylinders will offer 85mm stroke and 88mm bore for around 3103cc capacity.
I have no pricing or other information yet, but I will post it up as soon as I know.
In the meantime Kameari do offer a similar set-up, using a modified LD28 crank to get 85mm stroke, 138mm conrods and 89mm pistons (29mm pin height) for 3171cc capacity.
The OS Giken crank will be a much more impressive item, most likely a full-counter-weight billet type, suited to much higher rpm. The conrods appear to be similar to the forged chrome-moly H-beam type in the OS Giken RB30 engine. I better stop writing now...