From the world of business:
Amoco (American Oil Company)
Alcoa (Aluminum Company of America)
Motovlog, for [del]bloggers[/del] vloggers for whom a video log ain’t worth the effort unless you’re doing it while riding a motorcycle.
Humongous (huge/monstrous/enormous).
There’s also Hanukwanzmas, which is certainly not standard, but you can find references to it on the net. (However, Hanukwanzmasolstice, which is a quadruple portmanteau, seems to be mine alone.)
Sidetrack: This thread got me thinking about whether a portmanteau has to be made out of different parts of the component words (usually the beginning of one word and the end of another, e.g., smoke + fog = smog). I haven’t found any source that says yes, but to me, portmanteaus that are made like that seem more like “real” portmanteaus than ones that are made by stringing the beginnings of two or more words together.
Reported for possible forum change to IMHO.
There’s the Bi-Monthly Science Fiction Convention, or Bi-Mon-Sci-Fi-Con.
You mean repfopofochatoim.