Adding kernel modules: Interesting, hope I'll get to look at it some day - but I'm just happy to use your modifications.
I installed VMware tools the standard way, and because these VMs will be used mostly as servers, I don't know if I will take the time to try out your more comprehensive customization. But if some of them are to be run under Windows, I might try!

As for grub, maybe I should format the virtual disk as ext2/ext3, and install legacy grub to it? But for my present use, using isolinux boot is adequate for now. Using the flash-installer has got a lot of appeal to me..

And I must say, packing your minirt with the ISO, and using it from the first guest boot on, seems so simple and safe to me.