AKG makes shock mount replacements, they are the only ones that I recall seeing anything similar.
I dont know if they are what you need.
See the blue product on this page: EDIT: Seems to be the TOP only piece
Seems that e36 and e46 has so many options and we in the e90/e82 space are scraping for options. Perhaps in a year or 2 there will be more.
Alternatively: Turner has this bushing OEM replacement kit
Turner Race application:
EDIT 2 - Ignore the following, dont think i am correct because e46/e36/z4 parts may be too wide and will need grinding to fit (compare turner Race application for e9x and e46)
Do you think BMW e36/e46 and z4 lower mounts will fit? I looked and noticed that they are interchnagable for those years, maybe the new e9x e8x part has same dimensions even though the shape is different( square vs the older round)??
The difference also seems to be the mounting location. E9x e8x is on the suspension arm, while on e36 e46 is its on the car body. if they are the same shape it may work, but untested.