Tom,  Unfortunately the little Karaoke systems sold to consumers are
toys and will disappoint you and your audience.  I am personally very
fond of two "small" professional grade systems that you might be able
to find used:

1. Fender P-150 "Passport 150 Watt Portable PA System"  -- new, about
$475.  The system does not include loudspeaker stands, but it does
include the needed cables and a microphone.  It packs up nicely but
does not have wheels.

2. Peavey "Escort 2000 150 Watt Powered Mixer"  -- new, about $650.
Complete with microphone, loudspeaker stands and cables.  Folds up
into a rolling hard-shell suitcase -- it's very slick.  This system
has better bass response than the Fender P-150.

Five or six Fender P-150s are listed on eBay right now.  The highest
bid, on the one running the longest, is about $280.

The cost to rent one of these systems for a day might be $25 to $35,
and then you'd have an idea what you were getting into.  I hope this
is helpful.

Jody Kravitz
San Diego, Calif.

 [ Jody has provided loudspeaker systems for dance classes for
 [ several years.  -- Robbie