Yes, I did.
I can't confirm it is definitely 15HP now, but top speed at WOT increased by about 25%, so I would say it probably is. Equally, it hasn't gone bang so no ill effects.
I can't remember where I got the prices in the original post from - in the end I bought a complete new carb assy from the USA, which cost a good deal more - bear in mind that at the time my OB was nearly new, and to P/X for a same age 15HP would have cost more than the carb - for an older OB you may be better off just P/Xing it. That said the DF15 has been around a good few years now, so there may be people breaking them and consequently second hand carbs available.
Photos of the two carbs side by side - spot the difference