Hi flexiroute,

if you still need this knowledge I may write a short article about this if there's enough interest.

To be short, you create an usual tx in Electrum, export it to file as "hex", edit it in some way,
check with deserialize() in console, edit again until you are happy with the result, signtransaction(), broadcast()

It's important not to burn coins that you didn't intend to burn, and not to give away too much to the miner in the process :=)