The Bay Area’s burgeoning ukulele scene, which (like most ukulele scenes) has endless fun covering both 1930s trad and classic punk, has found another natural affinity in the gritty catalog of Tom Waits. And where goes ukulele, so go its companion instruments: the washboard, the singing saw, accordions, kazoos, and toy pianos — instruments that do what they do with the least-possible investment of either technology or capital, and that can be played passably without spending a decade at Juilliard. The singing saw wants a player with grapes, not cash.

Last night’s 21 Grand performance “Everything’s a Dollar in This Box: The Songs of Tom Waits on Cheap Instruments” opened with a “Step Right Up”-style bullhorn intro to the freak show, which featured 20 or so strummers, drummers and stompers in a handful of combinations. From solo to full-stage ensemble and everything in between, gravelly barn burners to sweet-like-molasses warblers. Performers (decked out mostly in 1930s/40s regalia) with names like 5 Cent Coffee, Liquor Cake, Stella!, Dogs in Doublets, and The Hobohemians. All, in their own way, stirring up the dust of a by-gone nation, using Waits’ burlesque as their jalopy.

It’s not like Tom Waits ever wrote a bad song in his life (okay, maybe a couple — he’s not a demi-god, but close enough for jazz), but it takes some kind of animal magnetism to make his songs soar. Just as a Dylan track can float like Jesus when transformed by Roberta Flack but sink like a stone when poot forth by a lesser voice, the Waits stuff seems to want one of two things: Delivery as stripped-down and gritty as his own, or huge and majestic.

Either way it’s a tall order, and unfortunately, not every song hit the mark. But those that did were enthralling. Stella’s version of “Soldier’s Things” was stunningly sweet (Kelly McCubbin’s 7’11” frame made it all the more so), and his uke playing was some of the evening’s best. Liquor Cake’s cover of “Pasties and a G-String” hammered it home – this stuff has to be delivered with a box of 16-penny nails. Fortunately, the bartender was handing out nails for swizzle sticks, so the crowd was well-prepared.

At one point, a slice of the audience started mock-sobbing as Spitshine and The Kid dragged our hearts through “Cemetary Polka” — and kept on wailing. In almost any other context, it would have been annoying. But somehow the accompaniment seemed fitting. No audience of stiffs here – the music wouldn’t allow it.

Spitshine De La Croix seems like he was born to play this kind of music, and is a total gas to watch, but I found myself wishing he wasn’t trying to sound like Waits – an attempt that took his performances dangerously close to “imitation” rather than “cover” (check 5 Cent Coffee’s version of “Chocolate Jesus” at their Myspace page). I like Spitshine best when he’s being his own bad self. And who knew he was an amazing beat-boxer to boot?

Anyway, it was all in fun, and most of that fun was damn talented. I don’t do American Idol, but got to thinking: If there was a way to do a version of that show limited to Tom Waits covers, some smart exec could pull all these orphans, brawlers, bawlers and bastards out of the woodwork and onto the national stage where they belong.