I had a few combinations that made it (painfully, in some cases) to 22 then were scrapped, when Stamina/SO's failed to have enough impact to make them feel playable to me.
They were usually part of my attempts to escape the 'post-50 malaise' as I called it. I didn't play mutliple alts at a time, I played one toon to 50, or one of my 50's. I think the most toons I ever had at less than 50 at one time was two or three. So, after I'd gotten a toon to 50, I found myself sort of stuck and it'd take me a few weeks of random pootling around at 50 to get inspiration for a new character.
I had a Thugs/Poison MM that didn't even make it to 22. Something about the combination of particularly suicidal and squishy feeling pets (oh, the pyro's dead again, what a surprise...) and an endurance heavy secondary killed any fun in the combination. Plus, I already had a Bots/Traps MM that was created on the CoV headstart weekend that I enjoyed and made other MM setups sort of... disappointing to me.
I had He-3, An Ice/EM blaster that suffered from chronic endurance starvation, even after SO's and slotted Stamina.
It was a long painful road before my Ice/Ice tanker (my first tanker) became fun, and he nearly got deleted, but eventually I got the hang of things and he became really hard to kill if I was paying attention. He made it to 50, and got me sort of hooked on tanking.
Springheeled Jack, my original Stalker got deleted for being too damn squishy and ineffective. He was EM/DA, IIRC. After stalkers got buffed, he was rerolled as DM/SR and as 'Springheeled Jacques' as someone had taken the original name in the meantime (which was fair enough, he was deleted partly for a character slot and partly so someone else could have the name if they wanted it)
I had Raffles, my SS/Invuln Brute who was originally rolled as EM/EA on the CoV headstart. He was killed off at about 16 or so, due to EA being tissue paper back then, and EM draining me dry of endurance. Once rerolled to SS/Inv, it felt better.
I'm sure there were others, but I can't recall right now.
Oh, and someone earlier in the thread complained about Kinetic melee being too slow? It wasn't really. It just felt it because of the sound effects. My KM/SR flying scrapper was all sorts of fun in a mostly single target sort of way. Especially since the speed buff to Hover came in shortly after I'd chosen flight/hover as his travel pool <grin>