No Malmsey here either. I used Bual, Campari, and Booth's. The Bual Madeira was certainly sweet enough, but I'd cut down its proportion a little next time. A decent drink, but not as good as the very similar East India Negroni.

Our (brand new) bottle of Blandy's doesn't say "Malmsey" but it does say doce ("Rich Madeira"), which I guess is close enough; it's definitely on the sweet side. Used Martini & Rossi Riserva Speciale Bitter and equal proportions. Don't know if it's really drier; depends on what vermouth you're comparing it to. I'd say it's a nice but subtle change to the flavors in a classic Negroni. Kudos to Ms. Miyazaki and Bar Tenderly.

Having no Malmesy, we had to do a work-around here...which was to use our Verdelho Madeira, add 2.5ml sugar syrup and apply a mist of Pimento Dram. We've no idea how this added faff stands up to the simplicity of the original but we enjoyed it.