Okay, here we go. A solution that can be used by any wizard capable of casting Tenser's transformation. Takes a bunch of prep, though.
1. Cast contingency on yourself: Whenever you say "Supercalifragilisticexpialidocious," you will dimension door 20 feet away.
2. Don heavy armor.
3. Have your fellow PCs encase you in plaster up to your neck. Allow it to harden.
4. Say "Supercalifragilisticexpialidocious." Contingency triggers. You can choose to take objects with you when you dimension door; choose not to, however, and you can leave the armor behind. Do so. The armor is now encased in plaster, holding it in position.
5. Cast contingency again. This time, whenever you are under the effect of Tenser's transformation, you will dimension door into the nearest set of armor that is encased in plaster.
6. Rest to get your spell slots back.
7. Cast Tenser's floating disk as a ritual, and put the armor on it. Tote it around with you as long as necessary. (You think it's a coincidence that Tenser created both of these spells?)
8. When you're ready to break some heads, cast Tenser's transformation. As soon as the spell takes effect, you teleport into the armor, which is already assembled and positioned for your body to occupy.
9. Have your fellow PCs break the plaster.
10. You are now in heavy armor and under Tenser's transformation. Break some heads.