Post-mortem remains

The world becomes home to more dead people each year. It's getting crowded. There's been, for eons now, a fascination with preservation of humans after death. One way we attempt this is through our children. Another way is soaking our decaying remains with formaldehyde and other chemicals to turn our flesh into plastic. These bodies go into the ground with the purpose of keeping them intact forever. So much real estate is dedicated to dead bodies that contribute neither to society nor to the food chain.
Those who are conscious of this are turning to cremation. A description of this is hardly necessary, and we know that grandma's ashes can either be dumped into the ocean near where she kissed grandpa for the first time beneath the sunset, or they can sit in the garage, in an urn, where no one will find them until your own grandkids are looking for a spot to park your mortal dust.
Something new that has been done recently is the compression of ashes into gems. Just think... a little piece of grandma can rest on your finger or on a chain around your neck, where you can fondly remember her until the rent is due and you need to pawn it for cash in a hurry. LifeGem is one of the big producers of compressed-ash gems. (For those of you who are scratching their heads, ashes are made from carbon, and carbon is what gems are made of.) I haven't looked into what processes are used to manufacture such gems, but I'm sure they aren't cheap. My understanding is that usually they use just a portion of your loved one's ashes to make a gem, which leaves you with a whole lot of mess left over. What part did you make into a gem? Something important like the heart, or perhaps something less important like the spleen or the left hand? You could always have all of your ashes converted into gems, but this would likely be prohibitively expensive. Apparently, it is not possible to convert all your ashes into one giant gem.
I think what I'd like to do is have my head cremated separately from my body, in just a cardboard box that will disintegrate in the flames with relatively little residue. My head ashes could them be converted into a reasonably-sized gem, perhaps cylinder-shaped like most laser-medium jewels. Then, when light is piped into the gem, the outputted laser is not just polarized light, but a projection of my soul as well. This gem could be placed within a giant robot where the gem is connected to the robot brain, thereby reincarnating me into a giant robot.
This is assuming that I would have enough personal wealth to build such a construct. To rely on someone else's resources (e.g. the government) almost certainly means programming that would place me in servitude to the provider of such resources, and I could be used to wreak havoc and terror across the globe, without being about to keep any of the booty for myself.
Any thoughts?