Butter in beer - probably not good, considering diacetyl is usually an off flavour.
The butter and vodka may be OK, it could come out like butterscotch shnapps but I dunno.
A simple green dragon recipe is a small bottle of lemon extract (90%+ alcohol) with about a 1/2 - 1 gram of bud in it, heated, then mixed with cola or similar. There's a link on wikipedia to that recipe under the external links section.
Personally I'd make an extract in high proof grain spirit and then add a few drops of it to each bottle at bottling time. But then if I had enough bud to throw around like that I'd probably just smoke it.