A better way to Calculate and Store Lightmaps?

[Demented]

Hey track builders and developers,
Seems every time there is an update I have to recalculate lightmaps on at least a few maps, especially ones with dynamic lighting and those can take 10 or 15 minutes each in Ultra on some bigger tracks. This can add up to a lot of time. The lighting looks beautiful on maps done in Ultra and I wouldn't want to see that lost, but I feel like I'm spending way too much time recalculating shadows. It may be time for some brainstorming to come up with a better method. I don't mind calculating shadows when I finish making a map, but I've got some maps I've had to recalculate 18 to 20 times now and that adds up to three or more hours. So, is it possible to come up with a new method for lightmapping? or even just a way to patch into existing lightmaps and just calculate the sections that were affected by updates? I'm sure a solution can be found with some good brainstorming put into this. I can't be the only one who would rather spend more time building or racing.

Also; This may be an odd question but, can the lightmaps of saved replays be recalculated?