@tomdx, Thanks for clarifying this. I was wondering if there was a way for a script to sign a delegation certificate. So it looks like the situation right now is as follows, but eventually everything may be stakeable:
| Payment Portion of Address | Stake Portion of Address | Stakeable? | |
|---|---|---|---|
| 0 | key / script / contract | (none) | no |
| 1 | key | key | yes |
| 2 | script / contract | key | yes |
| 3 | key | script / contract | no |
| 4 | script / contract | script / contract | no |
Case #1 is the common situation. I’ve been testing case #2 on testnet with a simple script.