Energy confusion:
Sorry, I was sort of vague. There are 2 feats in T&B: Energy Substitution and Energy Admixture. Your feat is a hybrid of both of these, which is cool, but I think you end up charging too much to mix energy.
Energy Sub: you can sub out an energy type for another type. SL +0
Energy Admixture: you can add an additional type of energy to a spell. The strength of the new energy is equal to the old one.
Example: Take fireball. Lets say you want a fire/ice ball. Now it does 10d6 fire damage and 10d6 cold damage, but it is 3 levels higher.
I think admixture provides good bang for your buck, but is generally too expensive to see much play. Your Transmute Energy is similair in that you can mix energies, but you charge +1 spell level just to have a mix of energies (I think its too high).
For instance with your feats:
I could take fireball, my wizard's favorite spell, and if I was fighting a salamander, switch it to an iceball for SL +0.
I could perfect it, ensuring a 60 pt fireball for SL +3.
I could expand it, filling an 80 ft diameter for SL +3.
Or I could mix the energies, making it part ice, part sonic, part acid for SL +3.
The last one is weird. First of all, I don't know why I would want to (perhaps fireball is a bad example for this feat) and second of all considering the other effects I could get for SL +3, why would I bother? Although on the whole your feat is more useful than either T&B feat.
I like stretch spell a lot, but day/level scares me. Make sure that an elf's 4-hour meditation counts as being "not awake" and it should be fine. Im not really sure day/level makes sense if you have to be awake, but I suppose in extreme situations it could be very very cool. (I picture a haggard wizard with deep shadows beneath his eyes following a monster through a trail to some hidden place muttering "just a couple more hours...").
Sorry about misreading chain spell! At any rate, the WotC version also has a line about not hitting a secondary target more than once, I just neglected to quote it.
One of the things that kept combos from turning a touch spell into a ray spell and then chaining the ray was that chain spell required the original spell to be a ray. Not sure how you want this to work for your game, but it could be a limiting factor on Ranged touch spell.
Technik
Edited: I love Hetha's Gambit man, keep up the great work!