Well, you can put any kind of scripts into the wallet's code, but without a specific application (a user case), I don't see how I could add anything more.
So far gocoin supports the following output scripts:
* P2KH address (a regular bitcoin address)
* P2SH address (that's for multisig)
* NULL output describing the next one's encrypted constant (for stealth payments)
* NULL output with an arbitrary data (e.g. to attach text messages to transactions)
Adding other kind of output scripts is not really a challenge, but I need a specific application for it, before I can put it in.
As from the node's side.
Gocoin node (unlike bitcoin-qt) does not split transactions into "standard" and "non-standard".
As long as the fee per byte is efficient, it will get routed, despite of a content of the script.
The most basic application is to make the transaction not redeemable for a given number of blocks. While it's clearly not a feature that will be currently used by many users, there are applications being built on top of the bitcoin blockchain that can take advantage of such features.
In any case, it's good to know that the wallet can be easily modified to support different output scripts.