Just thowing this out there... maybe it's been discussed before. What do " you " consider a collectable electronic slot ? I remember when the Bally Bucaroo's with animation, the Bally Circus, Bally Roulette brought "good" money.
There is a Roulette machine about 32" X 65" and 36" tall... had complete roulette layout, nice, big spinning wheel under glass....you could turn a knob on the front to navigate/ light up all the betting possibilities, chink in your quarters... and push the button to start and ball would come out/ roll around and stop on one the the wheel's holes. Machine would then calculate and pay out winnings (if any) Not many built because of the " Johnson Act" ...(gambling act).
Talking about bulky machines, how about the JJ Parker Craps Machines in Vegas circa 1970's - 1980's. they were huge and heavy as well. I remember they had a hollowed out wooden box inside the cabinet with a couple "clackers" for the sound effects of "shaking the dice" before the roll !
Gambling Horse Races (Video) on the large data disc (along the size of a 33 1/3 LP) Had the race "called" with sound effects that made you believe you were there!!..Saw a few at Sam's Town when they were the "new" gambling joint way over on the East side of Las Vegas....The Horse Race machines didn't go over too well...maintenance problems.
I could go on....you see the tide of technology... electoro-mechanical.... all (primitive) electronics...hand wired ciucuit boards....eproms... and now....
If you have a "collectable" Electronic slot... chime in... AND don't leave out Current / New stuff that's out or coming out !!
Thanks for your "ears" ....oh yes...