Churned out with the regularity of comic books, with which they have lots in common, pro-wrestling videotapes have become surefire sales smashes with fans who love to see just how garish this stuff can get. (And now, ladies and gents, one of the Bushwhackers bites a Natural Disaster on the heinie!) Summer Slam 91, a pay- per-view event staged at a packed Madison Square Garden this past August, brings together nearly two dozen wrestling heavies. In the main event, ''The Match Made in Hell,'' Hulk Hogan joins forces with the Ultimate Warrior to take on a tag team led by Sergeant Slaughter, who dresses up to look like Saddam Hussein. The matches are choreographed like Blue Light Special versions of Rocky; the underdog rallies at the end and sits on his opponent's face.
In a second main event, ''The Match Made in Heaven,'' ''Macho Man'' Randy Savage marries his honey, Miss Elizabeth. Although most of the tape is lifted whole from the show that aired on cable, Coliseum Video has added highlights from the wedding reception, in which the happy couple dances to the love theme from Ice Castles. But all this can get monotonous, except to the wrestling connoisseur, and there's some offensive, homophobic humor. Want camp and big shoulders? Try a Joan Crawford movie. C-