Sounding good!!  

If I recall correctly, a 3/4 cello has around the same body volume as a dreadnought sized acoustic guitar. So using a guitar might lack a little of the low end resonance, but could still be close enough to sound at least somewhat cello-like. 

Getting the action high enough to be able to bow it would take a large amount of rework and etc.  But as a cool sounding instrument to play with, it doesn't really need that.  I don't imagine it would be strong enough to use a cello style endpin either, for playing it in cello position.  But a little stand or narrow little narrow table could do the job well enough of getting it to at least approximate cello playing position.

I have seen a cheap electric bass rather rudely modified by screwing a piece of wood to the back to use as a tailpin so it could be played like a stand-up bass, but it was just plucked, not bowed.

If you wanted a closer instrument to compare your experiment to, the mandocello is the same range and a fretted instrument.  I sometimes tune one of my guitars as a sort of mandocello.  I usually tune it as C G D AA E, so I don't need to change strings and I have the double string sound to use as an option on at least one string.  

Fun stuff.