man! i would buy one right away... 2 in fact
all logical concerns aside, if we can assume that they just exist without worrying about the technical details (like you have to assume FLT in an I M Banks novel)
if there was a machine that could do proper gargalesis... dang...
what would be great also would be one that would do two people so you could strap in with your loved one and get tickled senseless together...
except if you have a loved one, and that loved one likes tickling enough get in a gargalesis machine with you... you probably don't need the machine
hmm
also, while we're are on the subject of self tickle devices, the closest thing i have come across (pun intended) is a cheap shower-head that was in one of the houses i rented when i was at art school... i still have it... i replaced it with a much nicer unit so i could keep it, because while being not that great for showering with it tickles like absolute crazy
i can't quite figure out what it is about it... the wholes are quite big, and there aren't many of them and they spread the jets quite wide, but i have never found another that tickles so well, and i have bought many in my search
i tell you, it works if you just hold it on yourself... but if someone else holds it and sprays you it is like "AAAAAAGHGHGHAHA I'LL TALK, I'LL TALK" - i have run it over the tummies, feet, and legs and... other... places... of a couple of ladies i have been lucky enough to shower with, and who, while not being as nuts about tickling as i am, quite liked a bit of a tickle... and they lost it completely, even when they used it on themselves
so after that slight aside... if you could also get a machine that replicated whatever it is about this cheap plastic shower-head that tickles so much, and apply it all over you (probably with slight vibration or movement of the jets) while you were fastened in place... that would also, perhaps, provide a most satisfying solitary tickle experience