no. but it eMMC part1 (MyDocs) now is workinf so it can be used for this. (but someone must write patch which will use this) but I think that saveenv is not needed...

I'm prepairing rx51 config to load bootmenu configuration from eMMC part1 file bootmenu.scr. So changing bootmenu entires wil not need to recompile u-boot. So in Maemo (or in all other systems) will be ulility update-uboot which update bootmenu.scr file in eMMC (MyDocs). We can use similar configuration file like in bootmenu/multiboot for configuring menu entires. And for security, if keyboard will be closed this file will be ignored (so if somebody damage this file, still can boot maemo5 in internal flash)