I have a number of Japanese Maples in cluding a typical, green, medium sized acontifolium. Does anybody know of any specialist growers or nurseries who may have tried to produce a red acontifolium?
I haven't heard of any progress in that area. As far as I know, there aren't any red Acer Japonicums at all. So it would be difficult to do this unless it was crossed with a red Acer palmatum. Although, it would be very unlikely that the leaf shape would remain the same. But who knows, maybe there is one out that is being evaluated as we speak.
The only plants available are thought to be Shirasawanum crosses with Bloodgood or a similar red Palmatum. There are several including Yasemin and Johin I think. If you look up World Plants website they have pictures of some of these. None has the leaf shape you are looking for. David
As Picea mentioned, there are some red A. shirasawanum varieties. Here's a link to some at worldplants.com
The Johin variety looks nice, but both of them are listed as growing to 25-30' tall.