955 Speed Triple Top Yoke

I'd contact a company who build bikes and ask the question as they have most probably had a lot of experience and could guide you

 

Aftermarket conversions look even more expensive than OEM!

The top yoke from a Speed Triple of the same era (1997 - 2006?) should fit, though I don't suppose that's likely to make them any cheaper - or more easily available! But it's a possibility. Good luck with the search.