How to create blur effect for 3D widgets?

I got really excited with the addition of the new blur effect added to UMG in 4.15, as this is something I’ve been wanting for a long time, but it seems that due to the way it’s developed, it won’t ever work for 3D widgets, which makes it useless for me.

According to the developer’s notes: *Background blurs cannot be used correctly in a 3d widget component because the scene behind it has not been rendered yet so it doesn’t have all the data to blur.
*
So… I’m looking for ideas how I could build my own blur material/post-process/etc to get around these limitations. For my purposes, I think it would be completely acceptable to use the scene’s data from the previous tick, but I’m not sure if that’s even possible.

Has anyone ever done this before or have some suggestions where to start?

Thanks guys