Do they make colored 1156 or 1157 bulbs?
Or possibly rubber/ plastic bulb covers?
I'm not using them for some "snazzy" exterior crap,
Just for a little project I'm working on.

 

Yes, any ricer store (including Pep Boys) will have colored bulbs in those sizes.

I have a set of "chromed amber" 1157 bulbs from Vatozone in my front "clear corners". Mirror when off, amber when lit.

Sylvania also makes a Silverstar 1156 and 1157, that are a greenish-blue when off, and amber when lit.

However, colored plastic as a diffuser will give you better color and light than a colored bulb. Similar to how stock clear bulbs are used under red plastic for brake lights.

 

Ebay has damn near everything, also autolumination will have a selection as well (scroll down)...