Chinese Languages With Multi-syllabic Readings Of Single Characters
The closest to your idea are the contracted characters, most of them created during the 20th century. Some examples include


圕 tuan1, short for 图书馆
瓩 qian1, short for 千瓦, kilowatt, (where the thousand/kilo part is actually wrapped right to the 瓦 character for aesthetic or 'economic' reasons, despite the fact that the multiplier of quantities always comes first), or
兙 shi2, short for 十克, decagram (same story as 瓩)
浬 li3, short for 海里, nautical mile, yet another contraction.


Some other similar characters have not yet made into the Unicode tables, so you won't find them online. 

I think it's important to point out that these are modern day contractions owing to the nature of all language users: trying to be economical in writing. These characters popped up for the same reasons like the dollar sign ($), or the the copyright sign (©) and so on, they are pure abbreviations to save the writer from having to write out multiple characters. I think it's hard to accept them as real multisyllabic characters, mainly because they tend to have a monosyllabic reading, too.