1) convert disk format
2) make the VM boot under the different VM environment
For now, I'm addressing item #1. The standard recipe is to run qemu-img on the .vmdk file to create a qcow2 disk image. Unfortunately this doesn't work in my scenario because I'm using a vmdk split into sparse (2GB) files, which causes the standard invocation to fail.
Assuming that you have access to both a set of VMWare and QEMU binaries available, this can be achieved with a two step process:
1) convert from split files into single, growable image file. Invocation for this is:
vmware-vdiskmanager -r "source.vmdk" -t 0 "temp.vmdk"
The option "-t 0" tells vdiskmanager to create a destination disk image which is growable and monolithic
2) use the standard approach to convert the monolithic file into a .qcow2:
qemu-img convert -f vmdk -O qcow2 "temp.vmdk" "destination.qcow2"
At this point, you have a disk image that will be accessible by software looking for a qcow2 format file. After verifying that you can access it, feel free to delete the temporary file temp.vmdk.