Portishead released its albums as double lps at 45rpm. It sounds great, but you have to stay close to the turntable; just one or two songs and then you have to flip it. It seems to be the catching on.
But before this, Angel Records had a series of 12' lps that played at 45rpm, also because of sound quality. It was called the "Angel Sonic Series".
I'm thinking of buying one of those, actually.
Oh, since these other related topics came up:
Faith No More's King for a Day was realeased as a bunch of 45 singles. yum.
And The Beach Boys released Good Vibrations as a 78rpm single for Record Store Day.