I've always thought that there is a special kind of insanity or psychedelia about Piper at the Gates of Dawn which can hardly be touched. Sure there are oodles of variations of psychedelic-ness out there but the purity of a song like "flaming" has a strength that is hard to top.
Strangely i've always thought that one of the closest things i've ever heard to channel that insanity was the Traffic song "house for everyone". I cannot listen to that song without laughing and thinking of how over the top it is. The only thing else i can think of similar at this moment are Mark Wirtz produced songs like "sam" or "weatherman". Sure people like Robyn Hitchcock and even Julian Cope are known for their Syd Barrett-ness but they do not really convey the complete insanity of Syd during the Piper at the Gates of Dawn time period.